Updated: 10:25 a.m.

Federal prosecutors rebutted accusations Monday that they hid vital evidence from defense attorneys for Alaska Sen. Ted Stevens (R) but acknowledged that they will not call an expected key witness in the lawmaker’s trial.

Stevens is charged with filing false financial statements over an eight-year period to conceal the receipt of more than $250,000 in gifts — primarily in renovations to his Girdwood, Alaska, home — from VECO Corp., an oil services firm, and its executives. He has pleaded not guilty.

Stevens’ defense attorney Craig Singer filed a motion late Sunday asserting federal prosecutors did not disclose information obtained from interviews with Rocky Williams, a former VECO employee whom several witnesses in the case have identified as the day-to-day supervisor of the Girdwood renovations project.

The motion sought to either dismiss the seven-count indictment against the lawmaker or, alternately, to declare a mistrial.

In particular, the motion stated that Williams denied to Stevens’ attorneys that he worked at the Girdwood site full time, asserting that he spent time on other projects even though he billed his time to the renovation.

“The government’s decision to withhold this information has prejudiced the defense. Had it been disclosed, the exculpatory evidence would have been a significant theme of defense counsel’s opening statement, and it could have been used effectively to cross-examine the government’s witnesses,” Singer wrote.

Federal prosecutors denied those accusations Monday, asserting that defense attorneys were aware of the alleged discrepancies in hours Williams billed for the project.

Prosecutor Nick Marsh cited an e-mail provided by Stevens’ own attorneys that appeared to acknowledge Williams worked on other projects during the same period.

The e-mail to Stevens from Bob Persons, a longtime friend of the Senator, said: “I have to torment Rocky to keep him working on the chalet, rather than all the projects Bill keeps him working on.”

But prosecutors acknowledged they do not intend to put Rocky Williams on the witness stand. “For our purpose, we don’t think we need him,” Marsh said.

Judge Emmet Sullivan appeared critical of both sides Monday, opening the court session stating: “I’m disturbed about the content of this motion.”

Sullivan said he is not inclined to declare a mistrial or dismiss the case, asking attorneys for alternative solutions including recalling witnesses who have already appeared in the court: “Any other options for me to consider, defense counsel?”

In addition, Sullivan proposed making Williams available for a deposition in Alaska, although defense attorney Robert Cary indicated Stevens will push for Williams to appear in court: “We’d like him here as a witness, your honor.”

Sullivan continued to review the matter in the U.S. District Court for the District of Columbia on Monday morning, a decision is expected this morning.