(FORTUNE Small Business) – Shortly before dawn on a rainy morning this past summer, Harvey Jay Brown drove to an empty parking lot near his Tampa apartment, where he knew he'd be alone. Dressed in a T-shirt and sweatpants, he rigged a hose from the tailpipe of his 1990 Mustang through the hatchback, sealed the hatch shut with a towel and duct tape, then climbed back inside with the engine running. His body was discovered a few hours later, when people began arriving at the parking lot for work. Inside the car, police found half a bottle of champagne, two cans of Coors beer, an empty bottle of the painkiller Darvocet, and a fake Rolex. Harvey also left behind a suicide note requesting that he be cremated. It was June 9, 2003, his 39th birthday.

Steven Brown, Harvey's 37-year-old brother, found out what had happened later that day, when his wife called. He was driving on Long Island, where he lives and works, and from the hesitation in her voice he knew what she was going to say even before she asked him to pull over. He'd been dreading the moment for years. "He killed himself, didn't he?" Brown said. The news left him crying hysterically in his car, but it also brought a less predictable emotion: relief. After all, Harvey's suicide finally ended a dispute that had begun over the family cleaning business and had pitted the brothers--Steven, the younger and more responsible of the two, and Harvey, older and perpetually plagued by drug and legal problems--against each other for more than a decade.

Worse, Harvey wasn't the only family member who ended up dead. In 1997 the Brown brothers' parents had been murdered in their Long Island home, a crime that Steven had long believed Harvey--his brother, their son--was guilty of. Harvey had a motive: He was furious that he'd been passed over to run the business. And Steven, a compact, energetic man who will proudly tell you that he worked his way up from mopping floors, had spent the next six years persuading the police to press charges. In the process he had paid about a half-million dollars to private investigators and had even filed a civil suit against his brother for their parents' wrongful death. By the time Harvey drove to the Tampa parking lot to die, he'd been established as the chief suspect, and a grand jury was hearing evidence on whether he should be indicted, at last, for the murders. "Harvey always chose to take the easy way out," says Raymond M. Pierce, a criminal profiler who helped the Suffolk County police investigate the case.

The events sound almost like a script from Law & Order or Euripides. In fact, the Browns' story is merely an extreme--and extremely violent--instance of a common problem: succession in family-owned companies. There are about 3 million such businesses in the U.S., and only 30% of them will make it to the second generation. "It's not unusual for there to be disputes about who ought to be the successor," says Craig Aronoff, co-founder and principal of the Family Business Consulting Group in Marietta, Ga. "And it's not unusual for there to be sibling rivalry. Those things can eat you up." In the case of the Browns, they literally consumed most of a close-knit family.

Looking back, there were hints of tragedy to come, but many wouldn't become clear until much later. Both parents, Heyward and Ellen Brown, came from entrepreneurial families, so it seemed only natural that Heyward would start his own business. In 1977 he opened Brown Industrial Maintenance. A meticulous dresser and a born salesman, he quickly built the company up to about $1 million a year in revenue. To celebrate his success, he splurged on memberships in private golf clubs, expensive jewelry for his wife, and cars for his two sons. But by the late 1980s, after losing a key client, he suddenly found himself in financial trouble and had to declare personal bankruptcy. "He was a great salesman, but he was not a great businessman," says Steven.

At the same time Heyward began having problems with his older son. Growing up on Long Island, Harvey was, by all accounts, a normal kid--not violent, not troubled. He and his father shared a passion for cars, and they had a close relationship until the mid-1980s, when Harvey enrolled at the University of Tampa. Officially he was studying computer science, but he also started his own cleaning business, which took in more than $200,000 in revenue after just one year. However, Tampa was a party town, with lots of temptations for a college-age kid with money, and Harvey soon began doing drugs, mostly cocaine and marijuana.

His problems became more apparent after Steven moved down to Tampa to live with his older brother and study accounting at the University of Southern Florida. As teenagers the two had had their own friends, but they both liked cars, sports, and music, and they got along as well as most brothers. In Florida, however, Harvey was hostile and secretive, answering questions as to his whereabouts with "None of your business." He also took advantage of Steven, especially when the younger brother helped out at Harvey's cleaning business. Steven says he worked about 70 hours a week and got paid just $100. "He liked to have me as his slave," Steven says. "He was a control nut."

After months of listening to Steven's complaints, Heyward decided to check things out for himself, visiting his sons in 1986 at the house they shared. One night while he was there, two of Harvey's employees called the house, drunk and threatening to trash the restaurant they were cleaning because their paychecks were $10 short. Refusing to get out of bed, Harvey sent Steven to deal with it. When Steven got there and offered the employees checks, they demanded cash. He didn't have any with him, so he called Harvey. Ten minutes later Harvey showed up with a 9mm Beretta and shoved it into one man's mouth. After they ran away, Harvey turned to Steven and said, "Clean!" leaving him to finish the job. Back at the house, when asked by his father why he left Steven alone, Harvey answered, "I don't clean restaurants." The next day the father flew back to New York, taking Steven home with him for good.

The cleaning business wasn't Harvey's only entrepreneurial venture, though, and it wasn't the only one that led to trouble. A year later he was arrested and charged with arson after a deli he co-owned with a girlfriend burned down. Harvey was discovered inside the building while it was ablaze. He claimed that he'd happened to spot the fire when driving past and had run in to try to extinguish it. His girlfriend, who told investigators she believed he'd started it, later reported that he had threatened her life, and out of fear she left the state. But Harvey fought the arson charges and was acquitted, and Heyward invited him to move back to Long Island. Heyward also gave him a Corvette that he'd promised to Steven. "My father really pacified him because of the fire," Steven says.

By 1989, Heyward had decided to Shutter Brown Industrial Maintenance, and the family opened a new business nearby called Eastco Building Services. With debts still left over from his bankruptcy, Heyward didn't want to put the new firm at risk by serving as an officer, so Steven and Ellen became 50% shareholders, with Steven as president. Although it seemed obvious that Steven was a better choice--he'd worked for his father since he was 14, while Harvey showed up only sporadically--Harvey was infuriated at being left out. He would later insist that he'd come up with the company's new name and that he'd sanded the old one off the sides of its trucks. "I had an expectation that I was going to run the company," he would testify in the wrongful-death suit. Harvey also threatened to report his father to the IRS for alleged tax fraud; he believed it was illegal to close the old family business and open a similar one under a new name. After a few months he started a competing company, taking three clients with him. It hardly mattered, though--the new venture, like the others he'd started, didn't last long.

Meanwhile, Eastco began to thrive. Under the leadership of Heyward and Steven, then just 22, Eastco attracted customers like Genovese Drug Stores, Konica, and Waldbaum's supermarkets. After Steven cracked down on Heyward's profligate spending, they repaid $600,000 of debt. By 1992 the company had branched out into maintaining heating, ventilating, and cooling systems for government buildings like 6 World Trade Center (which was later destroyed in the Sept. 11 attacks) and the John F. Kennedy Library in Boston. Later Eastco diversified into construction.

As the company's prospects improved, so did Heyward's finances. On a 1995 business trip to the Virgin Islands, he and Steven bought themselves matching Rolex watches. Later that year each treated himself to a $60,000 Dodge Viper. Heyward and Ellen, then in their early 50s, invested in property in Delray Beach, Fla., where they were planning to retire. "Everything we had, we worked for," Steven says.

While Eastco prospered, however, Harvey continued to struggle, going from one get-rich-quick scheme to another. In 1990 he tried to organize a rock concert called World Party, but the event never happened. He worked briefly as a mortgage broker and a car salesman, but neither job lasted. He still got along well enough with Steven to be best man at his wedding in 1994, but he battled with his parents. Every few months Harvey would show up at their house and harangue them, saying, "You have everything and I have nothing," Steven recalls. Ellen, who was more sympathetic toward Harvey than his father was, often helped him out with money, recording the amounts in a notebook that police later found. But during an argument one day in 1997, Harvey told his mother, "You screwed me out of the business," and then insulted his father, who wasn't present, by saying, "I don't know how you can lay down with that filthy animal every night." Afterward Ellen resolved to break off ties with Harvey. She told Steven what had happened, and said she wanted to pay for Harvey to get psychological help--something it appears that he never did.

Steven, who usually acted as the family peacemaker, persuaded his parents to reconcile with Harvey a few months later and, with his father's permission, invited Harvey to Eastco's Christmas party on Dec. 16, 1997. Steven was ill with viral hepatitis and couldn't attend. Harvey was delighted to discover that Heyward had told employees about his sole business success--a beer bottle he'd invented with raised grips to make it less slippery. After patenting it, Harvey licensed the bottle to Stroh Brewing. "Just about every person that I met through my father, he had bragged to them and had shown them the beer bottles," Harvey would later testify. But Steven believes that Harvey was upset when he saw the size of the company his family had built without him. By then Eastco had more than 400 employees and was recognized as one of Long Island's fastest-growing companies. In his end-of-the-year speech, Heyward congratulated a manager on his promotion to vice president, and Harvey muttered that he should have gotten that job instead. Just days later, someone who overheard his remarks would have reason to report them to the police.

On Dec. 19, Steven's wife, Debbie, drove to Heyward and Ellen's house in Lake Grove, N.Y., a small town an hour east of Manhattan, to check on them. Normally the four talked every hour or two by telephone or on the company's radios, but the parents hadn't been heard from in almost 20 hours. At the house, Debbie found the doors locked and water streaming from the garage. She called Steven, who told her to stay outside. When the police arrived, they found Ellen upstairs in the bedroom, her skull cracked and an arm broken. Heyward's body was in the basement. His skull had been smashed six times, and there were puncture marks on his chest, most likely from a fireplace poker. In another room, near an overturned strongbox, the police found a copy of the parents' will, which divided the estate equally between both sons. (Steven and Harvey learned a few days later that their parents had revised the will to leave everything to Steven except the house, which Harvey would inherit.) Some jewelry, including Heyward's Rolex, was missing. The murderer had turned on a faucet in an upstairs bathtub, apparently to wash away evidence. Water was flowing down the stairs, and the kitchen ceiling had collapsed.

Detectives quickly concluded that the killer knew the house--there were no signs of forced entry--and had acted more out of rage than larceny. He had worn rubber gloves from the kitchen during the crime, rather than bringing his own, and afterward he had washed them and returned them to the correct drawer. Heyward was beaten more viciously than his wife, even after he was dead, and a potted plant had been placed on his prized car, a vintage Mustang. The killer had also tried clumsily to make the assault on Ellen look like a sex crime. An X-rated video was left in the VCR, two vibrators were placed on the bed, and her pants had been pulled off. Yet she hadn't been molested. "The murderer could not go so far as to have any sexual contact with her," says Raymond Pierce, the criminal profiler who examined crime-scene photos and police reports within days of the murder. Detectives soon came to suspect that Harvey was the killer.

The evidence, though, was entirely circumstantial. Even with a motive, prosecutors were not likely to charge Harvey unless they had a witness or more concrete evidence. "We were told from day one by the homicide department that the district attorney of Suffolk County back then would never prosecute a circumstantial murder case," says Steven's attorney, Howard Fensterman.

On top of the family tragedy, Steven still had the business to think about. Within days of the murder, clients and bankers began besieging Eastco with anxious phone calls, while competitors made offers to buy Steven out. About a week after his parents had been killed, he showed up at work, literally dragged out of bed by his wife. He assured his employees, many of whom were terrified that the killer would strike again, that the business would go on. "I didn't know what to do," he says. "They're looking at me, I'm looking at them. They're saying, 'This guy is on the edge.' " Without his father to take charge of sales, Steven began working around the clock, managing some 500 accounts, and over the next few months even adding new ones. (In 1999, the company would be named one of the fastest-growing Long Island businesses for the third time.) Sometimes he'd get on a plane on Monday and show up at the office in the same clothes on Wednesday. "It was a place to hide," he says. "Debbie was upset about it, because I wasn't spending time with the children or her, but she understood that I needed a place to lose myself. I had two choices. I could stick a gun in my mouth and kill myself, or I could go on." Still, it took him a month merely to walk into his father's office.

In the meantime, Harvey's behavior was raising nagging questions for both Steven and the lead investigator on the case, a Suffolk County homicide detective named Norman Rein. As Steven thought back to the day of the murder, he remembered getting a call from Harvey around noon--more than two hours before police believe the Browns were killed--explaining that he was about to catch a train into Manhattan to see his girlfriend. "Steven said, 'It's the first time my brother ever called me up to tell me where he was going,' " says Rein. "He said it half-jokingly, but it gave me the impetus to look more closely at Harvey."

Harvey's attorney and best friend, Michael Hills, committed suicide two weeks after the murders, asphyxiating himself in a car inside his garage. Steven later found out that Harvey had kicked a hole in the door of his own apartment after learning about Hill's death, then immediately rushed to the lawyer's office to collect any files on him related to the investigation. "I have reason to believe Hills may have known about the murder and that it may have been one of the contributing causes of the suicide," says Rein.

But although Harvey had been caught in some probable lies under questioning--phone records, for example, showed that calls had been made from his apartment in the early evening of Dec. 18, when he was supposed to have been with his girlfriend in Manhattan--the Suffolk County prosecutors still didn't have enough evidence to bring charges. And despite Steven's growing suspicion that his brother had been involved, he tried to remain on decent terms with Harvey. "I think what a lot of people didn't understand was that, more than anything in the world, Steven wanted it not to be Harvey," says Steven's longtime friend Kenneth Russo. Steven and his wife continued to welcome Harvey into their home, and Steven even offered his brother a $70,000-a-year union job repairing heating and air-conditioning systems. But within a few months he had to fire Harvey for skipping work and making sexual comments to a co-worker.

Harvey then began calling Steven and Debbie's house late at night to threaten them. He'd started spending time with bikers, and he often roared by his brother's home on his motorcycle. Finally Debbie obtained a restraining order against him. Police warned Steven that his brother was becoming dangerous. As protection, Steven got an attack dog, a Doberman pinscher named Akki, and bought a 9mm handgun, which he kept strapped to his ankle. His blood pressure went up, and he rarely slept through the night. Within months, Harvey was fired from yet another job, in New York City, and soon after a bomb went off in the building where he'd worked. No one was hurt, but he was considered a suspect, says Rein. Yet the police weren't able to press charges against Harvey for the bombing.

In October 1998, Norman Rein retired from the Suffolk County Police Department, and soon after Steven started to feel that progress on the murder investigation was stalling. Impatient, he hired a team of private detectives, eventually adding Rein, who'd begun working as a consultant. Steven tried to persuade Harvey to take a lie-detector test in December 1999, but Harvey refused, telling him, "I'm sorry it has to end this way." That was the last time they spoke.

Frustrated, Steven authorized his attorney, Howard Fensterman, to file a $17 million civil suit against Harvey, blaming him for the wrongful death of their parents. "We decided we were going to use the civil process to marshal enough evidence to present to the DA to compel him to prosecute," says Fensterman. It's unusual to file a civil case for wrongful death before a murder trial. (Usually the order is reversed, as in the O.J. Simpson case.) But the strategy worked: Although Harvey could have pleaded the Fifth, he spent six days testifying in advance of a civil hearing. And for the first time, he blew his alibi, admitting that he'd been on Long Island at the time of the murders, not in New York City as he'd told police. "Harvey made a critical error in judgment in subjecting himself to depositions," says Fensterman. "He wanted to take me and his brother on."

As Fensterman worked the legal angle, Steven continued gathering information outside the courtroom, even tracking down Harvey's ex-girlfriend and supposed alibi, Elise Paulino. Paulino had once been charged with prostitution, but later pled guilty to a reduced charge of disorderly conduct. Although, according to Rein, she'd resisted testifying in the civil case, Steven finally persuaded her to talk to him away from the courtroom. As it turned out, even Paulino wondered how involved Harvey might have been in the murders. "On at least two occasions," Rein says, "Elise asked Harvey, 'What were you doing that day?' He said, 'When you have a need to know, I'll tell you.' Another time she asked him something germane to the case, and he said, 'My attorney has advised me not to speak about it.' " Paulino refused to comment for this story.

And there was more. An inmate serving 18 years for robbery in an upstate New York prison claimed that Harvey had once offered him money to kill Heyward and Ellen Brown, even bringing him to their house. The inmate said he knew Harvey through drug buys, when he'd been Harvey's dealer.

All the pieces were coming together, and by early 2002, Fensterman was able to persuade Suffolk County prosecutors to reopen the criminal case. This was what Steven had been fighting for since 1998, yet when it finally happened he found himself torn about the likely result. In the early morning, he says, he sometimes went to his parents' graves with Debbie and prayed for guidance that he was doing the right thing. "There were days," he says, "when I wanted to call Harvey and say, 'Listen, I know we don't talk, and maybe you don't love me anymore, but run, because they're coming to get you.' "

As the pressure increased, Harvey's behavior got stranger. To defend himself against the murder accusations--and, he claimed, to catch his parents' killer--Harvey started a website called doublemurder.com, where visitors could pay to read his rantings against Steven and his lawyer. "Since Fensterman will probably get to question me about this website," a typical posting read, "here is one more questions [sic] for you: 'Why don't you stick your head up your ass,' you 'liar for hire.' " He also added pornographic cartoons and pictures of motorcycles to an area marked Just for Fun.

By this time, Harvey had returned to Tampa with the money he'd gotten from selling his parents' house. But his legal problems followed. He was arrested and charged with stealing a washing machine from an apartment he'd rented, and with filing a false claim that his motorcycle had been stolen in the spring of 2003. And in New York, a grand jury had been convened to decide whether to indict him for the murder of his parents. In June, on the day he committed suicide, Harvey was due in local court to face charges for the motorcycle incident. At 1:13 A.M., in the last hours of his life, he called a woman he'd been living with in Tampa, and they spoke for about 15 minutes, according to police records. When she asked him to come home, he refused. "You don't want to see me like this," he said.

It was Steven who flew to Florida to identify his brother's body and have it cremated. "When I saw him, I actually poked him to make sure he was dead," Steven says. "Isn't that crazy? It was like, Ding, dong, the witch is dead. I thought, 'Am I really going to be able to live my life now?' " A few days later, back in New York, he received a note that Harvey had mailed to him the day before his suicide. It said, I'll make amends with Mommy and Daddy when I see them. "Unfortunately, I lost my parents over money," Steven says. "That's really what it came down to--money and jealousy."

More than three months after Harvey's suicide, Steven and his wife say they still haven't been able to relax completely. They're moving to a new gated house in a location that Steven won't disclose. "The dogs and the gun and stuff are going to continue, because I don't know if we can live any other way," he says. And he still has moments of doubt about whether he did the right thing. After Harvey died, he says, "I asked myself, 'Did I cause him to do this?' No, he caused it himself. The only thing I did was make him fess up to something that he wasn't man enough to admit on his own."

As for Eastco, the business is thriving. In the six years since his father's murder, Steven has increased annual sales from $7 million to $40 million. He wants to raise that to $100 million by 2006, in part by expanding Eastco's construction and mechanical-services divisions, a dream he and his father shared. Steven now uses Heyward's old office, but the name on the door is the same, and a pair of his father's eyeglasses still rests on the desk. Often Steven wonders what his parents would think about how far he's taken the business. But mostly, he says, he just misses them: "My wife and I have always said we'd give everything back just to have everyone together again."