While on home detention in 2015 for looting his campaign fund, former Rep. Jesse Jackson Jr. told prosecutors of other possible crimes “by him and others” and offered to secretly record conversations as part of a federal investigation, according to a Justice Department letter obtained by the Chicago Sun-Times.

“Mr. Jackson has informed the government of potential violations of law by him and others,” reads the Aug. 16, 2015, letter from Assistant U.S. Attorney Daniel C. Richenthal in Manhattan to Jackson attorney John Colette.

Jackson “has indicated that he desires to undertake certain actions, including participating in monitored and/or recorded telephone and/or email conversations and meetings, with the intention of providing the government with additional information regarding these potential violations of law,” the letter also states.

It wasn’t immediately known what the other investigation entailed, what possible crimes Jackson might have told prosecutors about or whether the cooperation deal was formally entered into.

A spokesman for the U.S. Attorney’s office for the Southern District of New York declined to comment.

“I remember part of that agreement, but I don’t have the document in front of me right now,” Colette told the Sun-Times by phone on Monday. “And I still can’t comment on it. You can maybe try the office tomorrow if you like.”

Jackson couldn’t immediately be reached for comment. No one answered the door Monday night at Jackson’s home in Chicago’s South Shore neighborhood. Attorney Brendan Hammer, who is representing Jackson in his divorce proceedings, told the Sun-Times that Jackson would issue a statement on Tuesday.

Colette most recently represented Jackson in his successful bid on March 7 to cut in half the three years Jackson was to serve on supervised release following his time in a federal prison and a halfway house.

It turns out, however, that Jackson was having other dealings with the Justice Department even as he was serving out his sentence for stealing $750,000 in campaign funds with the help of his wife, Sandi, who also went to prison for her role in the scheme.

The two are now embroiled in a bitter divorce, with Jesse Jackson aiming to have the case heard in Chicago and Sandi Jackson arguing to have it heard in Washington, D.C.

Jackson left a federal prison for a Baltimore halfway house in March 2015. He was released to his home in Washington on supervised release in June 2015. As a condition of his release, Jackson wore a device on his ankle monitoring his movements.

The Aug. 16, 2015,  letter was written to confirm an Aug. 12 phone call that Richenthal had had with Colette to discuss Jackson’s offer of cooperation. The names of the targets were not included in the letter.

The Richenthal letter notes that on Aug. 12, 2015, Jackson made an offer, called a “proffer agreement,” to prosecutors offering his assistance. A legal proffer would have given Jackson the ability to tell prosecutors in general terms what he knows about a potential crime.

Jackson signed the Richenthal letter as “agreed to” on Aug. 19, 2015. Richenthal notes in the Aug. 16 letter that there is no agreement by the government “not to prosecute Mr. Jackson.” The copy of the letter obtained by the Sun-Times includes a signature line for Colette, but the document isn’t signed.

Richenthal remains in the public corruption unit of the Manhattan federal prosecutor’s office; one of his high-profile cases was the Oct. 5,2015 indictment of Ng Lap Seng and others for bribing United Nations officials.

Michael Sneed reported from Chicago. Lynn Sweet reported from Washington. Contributing: Tina Sfondeles

Aug. 16, 2015, USDOJ letter by cfusco1972 on Scribd