WASHINGTON — Sen. Ted Stevens' friends went out of their way to help pay his bills, according to court testimony Tuesday, even conspiring to cover up how much money they paid for something as minor as plumbing repairs at the senator's home in Alaska.

"I'll just tell Ted to give me a check," his friend Bill Allen said in a conversation, secretly recorded in 2006 by FBI agents investigating corruption in Alaska politics.

"You don't have to deposit it, you just have to make a copy of it," said Stevens' friend, Robert Persons, who kept an eye on Stevens' home when the senator was out of town. "Then if it ever did come up, you can say, `I didn't deposit that? Hell, I know I did.'"

The telephone conversations, played in court Tuesday near the end of the prosecution case against the senator, came as close to a smoking gun as Stevens' corruption trial has had. Stevens, 84, is on trial for lying on his Senate financial disclosure forms about more than $250,000 in gifts and renovations to his home in Girdwood, Alaska in recent years. The gifts were largely from Veco Corp. and its chief executive, Allen, who now is the star witness in a corruption trial that's been underway since Sept. 22.

Prosecutors have been working to establish a case that time after time, Stevens took gifts even though he knew he should have paid his own way.

But prosecutors have stumbled in their presentations, and Stevens' defense team has accused them of withholding evidence that would have been helpful to the senator's defense. Stevens' lawyers have tried twice now to have the charges thrown out and will argue again Wednesday in front of the judge for a mistrial.

On Tuesday, Brendan Sullivan, Stevens' lead defense attorney, continued to tear into the government's case when he cross-examined Allen, who has already pleaded guilty to bribing state lawmakers in Alaska. Sullivan worked to leave jurors with the impression that Allen deliberately held back information from Stevens about bills and that the senator would have paid them had he ever been sent an invoice.

Sullivan also sought to dismiss the idea that Veco got special benefits when Stevens came to the company's defense over a pipeline in Pakistan, a labor training program for the Russians, a logistics contract with the National Science Foundation and support for a proposed natural gas pipeline.

Sullivan on Tuesday questioned Allen about his plea deal with the government and the risks that his lack of cooperation would disrupt the sale of Veco last year to CH2M Hill, an international engineering and construction firm based in Colorado. The company withheld $70 million from the cash it paid the owners of Veco -- Allen, his three children and two top executives -- to protect against contingencies, including the possibility Veco itself were indicted.

But prosecutors came back swinging with the recordings Tuesday afternoon. Jurors paid close attention to the conversations between Allen and Persons and openly guffawed at the salty exchanges.

One of the conversations shows the two were especially irritated in early 2006 after Allen sent a plumber he knew to make some emergency repairs to Stevens' boiler. The plumber sent an invoice for his work with the notation "labor paid by Bill" that Persons forwarded on to Stevens.

Stevens saw the notation and got annoyed, according to testimony. He sent Allen's secretary an e-mail saying he wanted to pay the whole bill, including labor costs. Allen had had it split in two so that he paid the $1,080 in labor and Stevens got the $1,187 bill for parts.

On Feb. 16, Allen called Persons to ask him about why the bill went to Stevens marked with "labor paid by Bill."

"Oh (expletive), I didn't even see this, oh, labor paid by Bill. Ouch. I didn't see that, I'm sorry," Persons said.

"Oh (expletive)," Allen said.

"Well, it went straight to his house," Persons said.

"Yeah, but I got an e-mail from ... that he's got to talk to me," Allen said, "and I've already taken care of that (expletive) bill.

"I just looked at that and I didn't ... I know you didn't want him to know that, did you?" Persons said.

"Well, that, and I didn't want everybody to know," Allen said.

Allen testified earlier in the day that although Stevens initially offered to pay him, Allen never sent him an invoice, and Stevens never again offered to pay.

But Allen also testified Tuesday that he thought Stevens wanted to pay. Allen said he remembered having a conversation about the amount of work Veco had done on his house, as the two men were getting into Allen's car outside the Double Musky, the restaurant in Girdwood owned by Persons. "He said, "I know you're putting more work in there than what you're saying,'" Allen said.

Investigators had been recording Allen's conversations secretly for some time as part of their investigation, but he was not aware of it until Aug. 30, 2006, when the FBI searched his home and office and accused him of bribing state lawmakers. Allen agreed to cooperate with prosecutors and record some conversation with Stevens. Some of those were played during Monday's testimony.

The prosecution is expected to wrap up its case Wednesday.