(FORTUNE Magazine) – There's a great scene in the HBO TV series The Sopranos where the son of the fictional Tony Soprano learns from the Internet that his father is not a waste-management executive, as he'd claimed, but a Mob boss. This isn't far-fetched. Thousands of mostly low-budget Internet sites cover crime and justice, including a handful devoted exclusively to organized crime.

Now a big player has moved into the neighborhood. Two former investment bankers and an ex-TV correspondent have raised $23 million, hired 75 journalists, and launched APB Online (www.apbonline.com), which they want to make the dominant Website about crime. "We want to build the first Internet brand in the most intensively followed genre in all of media," says Marshall Davidson, 56, founder of APB Multimedia. His partners are Matthew Cohen, 32, a former Wall Street colleague, and Mark Sauter, 39, who worked for the TV show Inside Edition. Backers include BancBoston Robertson Stephens, Hambrecht & Quist, and Gabelli Media Partners.

Their APB site--the initials stand for "all-points bulletin"--offers breaking-news coverage of major crimes, analyses of government policy, tales of unsolved mysteries, missing-person reports, tips on crime prevention, even reviews of TV cop shows and Patricia Cornwell novels. All 1,300 pages of Frank Sinatra's FBI file are posted. So are files tracking Liberace and Marilyn Monroe, plus government registries of sex offenders. (Another 3,000 Freedom of Information requests are pending.) Soon users will be able to punch in zip codes and pull up local crime stats. And Pulitzer Prize-winning journalist Sydney Schanberg just joined APB to oversee its investigations.

Will crime pay for APB? Only if sponsors decide they need to reach an audience of crime buffs and the safety-conscious; it's not clear how many burglar alarms will be sold on the Internet. Meanwhile, APB plans to spend $10 million on advertising to raise its own profile.

--Marc Gunther