Government Exhibit No. 1094 is an undated photo of Sen. Ted Stevens, second from left, helping his one-time friend, Bill Allen, haul his catch on an Alaska fishing trip. (Department of Justice)

Thank-you notes written by Alaska Sen. Ted Stevens to a longtime friend, oil company executive Bill Allen, emerged today as key evidence in the lawmaker's federal corruption case.

Stevens, the 84-year-old Alaska Republican, is on trial on charges he lied about gifts he received from Allen, including $250,000 in renovations to his home near Anchorage. Allen testified he never charged Stevens for much of the renovation work, saying he "liked" the senator and "wanted to help" him.

In one 2002 note, Stevens thanked Allen for the home improvements and asked for a bill, The Associated Press reports.

"Thanks for all your work on the chalet. You owe me a bill. Remember Torricelli, my friend," Stevens wrote, referring to former Sen. Robert Torricelli (D-N.J.). "Friendship is one thing, compliance with the ethics rules, entirely different."

Torricelli, 57, served 14 years in the House was elected to one term in the Senate in 1996 but decided not to pursue re-election in 2002 after it was discovered he took improper gifts from a contributor, including a $9,200 Rolex watch and 12 handmate Italian suits. The Senate Ethics Committee "severely admonished" Torricelli.

In the note, Stevens said he had asked a mutual friend, Bob Persons, to talk to Allen about the bill. But Allen testified that Persons had a different message when he arrived.

"Bill, don't worry about getting a bill," Allen recalled Persons saying. "Ted's just covering his ass."