NEW YORK (CNNMoney.com) - The corporate trial of the century kicked off this week with Enron prosecutors painting a grim picture of a company governed by greed and self-interest, with little respect for its employees or for the investment community that sunk billions of dollars into its shares.

It's an image that defense attorneys for Enron founder Kenneth Lay and former chief executive Jeffrey Skilling will work hard to refute next week as the defense prepares to cross examine the government's first witness in the case, Enron's former executive vice president of investor relations Mark Koenig.

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The decision to present Koenig as the first witness was a smart move by the prosecution in a case that's certain to be highly technical and somewhat tedious as it progresses over the next several months, said Jacob Zamansky, a former federal prosecutor.

"All of the company's information goes through the investor relations department," Zamansky said. "Koenig has a key perspective of what went wrong because he [was] the window that [showed] the inside of Enron to the public." And what Koening communicated to jurors during two days of questioning from prosecutor Kathryn Ruemmler certainly appears to be a blow for the defense.

Koenig testified that the company massaged its earnings numbers to meet analyst consensus estimates with the blessing of senior management -- a move made to preserve Enron's stock price. He also said both Lay and Skilling blatantly lied to analysts about the true financial health of its various business units. In particular, the company hid losses from its highly-touted retail energy business and misled investors regarding the type of revenue its struggling broadband unit was booking.

To support his testimony, the prosecution presented internal documents that highlighted the many challenges the company faced and contrasted those private documents with public video and audio tapes in which the top executives painted a rosy picture of the company to the investment community.

While it looks like a good start for the prosecution, it may not be prudent to hand the that side a victory just yet.

"Often times, the government's case seems strong on direct only to be totally obliterated on cross," said Barry Boss, a former public defender and managing partner of the Washington D.C. office of Cozen O'Connor. "It's like trying to predict who wins the Super Bowl after the kickoff."

Defense attorneys Michael Ramsey and Daniel Petrocelli are set to cross-examine Koening once prosecution wraps up its questioning on Monday. Legal experts expect the two seasoned attorneys will emphasize Koenig's plea agreement with the government and his own admission that he sold stock in the company -- netting over $700,000 -- based on insider knowledge that Enron was in trouble.

"If he's willing to lie to investors and line his own pockets, then he could be willing to say what the prosecution wants him to say," in order to avoid a jail sentence, Boss said.

Koening pleaded guilty to securities fraud in 2004 and told the jurors Thursday that he now faces 10 years in prison, over $1 million in fines and 14 lawsuits over his role in the Enron collapse. Other than a letter from the government stating that he is cooperating in the case against Lay and Skilling, he has no guarantees that the judge will be lenient, he said.

Boss, however, dismissed the notion that Koenig won't receive deferential treatment for his testimony, calling it "prosecution 101," and expects the defense will hammer in that notion on cross-examination to raise doubt about the veracity of his testimony.

The defense will also try to play up the complexities of the accounting issues surrounding the case in order to bolster its contention that Lay and Skilling had to listen to the advice of hired accountants and lawyers. Those consiglieres included former financial chief Andrew Fastow, who is a star witness for the prosecution, and former accounting chief Richard Causey, who pled guilty in December and may testify for the government.

While Assistant U.S. Attorney John Hueston told jurors in opening arguments that the case against Skilling and Lay "is not a case about accounting. It's about lies and choices," the defense attorneys vehemently refuted that notion, saying accounting is at the heart of the matter.

"We want you to go there," Lay's attorney Ramsey told jurors.

Tom Ajamie, a securities lawyer and senior partner at Ajamie LLP, said the defense will "likely show [the accounting involved] was more complicated, with more nuances and shades of gray," and emphasize that Lay and Skilling relied on their lieutenants about accounting matters.

He added that the defense will also look to broaden the case by trying to play the audio and video tapes shown by the prosecution in their entirety, rather than the brief sound bites aired to complement Koenig's testimony.

This past week, Ramsey repeatedly sparred with prosecutors, saying that snippets of conversation were taken out of context in order to present the defendants in a poor light. After a particularly tense afternoon filled with objections, presiding Judge Sim Lake dismissed the jury early, citing "short-tempers" and told defense attorneys that he wouldn't waste the court's time by airing hour-long tapes that only had a few relevant segments.

Still, defense attorneys will likely to play back larger portions of the tapes that show that Skilling and Lay admitted to some challenges at the company, but were trying to be optimistic because they truly believed in the fundamental strength of Enron.

But it's still too early to know what Lay and Skilling will actually have to say if they decide to take the stand -- and if they do, that won't be for many weeks.

Brad Lewis, partner and head of the white collar crime group at Fenwick & West, said its a risky strategy to put a defendant on the stand, and the decision may depend to a large degree on how the defense feels the case is going.

In other white-collar crime trials, it hasn't always been a successful strategy. WorldCom's former CEO Bernard Ebbers, for instance, testified and was convicted last year. HealthSouth (Research)'s former CEO Richard Scrushy did not and was acquitted.

Now all eyes are on the outcome of the long-awaited Enron trial, which has become the poster child of corporate malfeasance.

Enron filed for bankruptcy in December 2001 after investigators found it had used partnerships to conceal more than $1 billion in debt and inflate profits.

The bankruptcy filing by Enron, once the nation's seventh-largest company, cost 4,000 employees their jobs and many of them their life savings, and led to billions of dollars of losses for investors.

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