Prosecution's Star Witness Takes Stand In DiMasi Trial This Week

In the federal corruption trial of former Massachusetts House Speaker Sal DiMasi, Joseph Lally was working for the software company Cognos when he won lucrative the state contracts at the center of the case. He is expected to testify as soon as Tuesday.

WBUR's David Boeri says defense attorneys will try to discredit Lally.

"They're gonna throw everything at him to suggest he is in fact "testilying," Boeri said, "which means that his testimony is bought for with this plea deal. The government knows this is coming, but they're trying to prop Lally up because they have emails, and other witnesses who are corroborating what Lally said, which is that he paid kickbacks to DiMasi and the others in order for Cognos to win the contracts.

"This is not at all a slam-dunk for the government — some of the best defense attorneys in the city are working for the defense here. So everything is at stake, and that's why this week, especially when you see Lally, there's going to be high drama."

Prosecutors offered Joseph Lally a lighter sentence, in exchange for testifying against DiMasi.

Several state employees involved in approving the state contracts are also expected to testify this week.