WASHINGTON (Reuters) - Federal prosecutors asked a judge on Tuesday to grant probation to President Donald Trump’s former deputy campaign chairman Richard Gates when he is sentenced next week, pointing to Gates’ extensive cooperation in multiple criminal investigations.

FILE PHOTO: Rick Gates, former campaign aide to U.S. President Donald Trump, departs after a bond hearing at U.S. District Court in Washington, U.S., December 11, 2017. REUTERS/Joshua Roberts/File Photo

Gates, 47, pleaded guilty in February 2018 to conspiring against the United States and lying to federal investigators.

A government filing in U.S. District Court for the District of Columbia to Judge Amy Berman Jackson said: “Based on his substantial assistance, the government recommends a downward departure and does not oppose Gates’ request for a probationary sentence.”

As part of his plea agreement, Gates vowed to cooperate with then-Special Counsel Robert Mueller’s office, including a case involving Gates’ former employer and Trump’s former 2016 election campaign chairman Paul Manafort.

Since that time, Gates has served as a star witness in three criminal trials, including Manafort’s, as well as the trial of former Obama White House attorney Greg Craig and Trump’s former adviser Roger Stone.

“Gates’ cooperation has been steadfast despite the fact that the government has asked for his assistance in high profile matters, against powerful individuals, in the midst of a particularly turbulent environment,” the government’s filing ahead of the Dec. 17 sentencing said. “Gates received pressure not to cooperate with the government, including assurances of monetary assistance.”

His attorney asked Jackson in a court filing on Monday to sentence Gates to probation, saying he had fulfilled every obligation and “devoted enormous energy and commitment” to the task, spending more than 500 hours with federal and state prosecutors.

Lawyer Thomas Green said Gates deeply regrets his decision to assist Manafort in his criminal misconduct while also breaking the law to enrich himself in the process.

Gates testified during Manafort’s trial in Alexandria, Virginia, in August 2018.

Gates told the jury he had helped Manafort falsify his tax returns, though he stumbled during the cross examination by admitting to unflattering behavior that included stealing money from Manafort and engaging in an extramarital affair.

Manafort was ultimately convicted by a jury and sentenced to 7.5 years in prison, though a juror later said in media interviews that none of the jury members put much stock in Gates’ testimony to help reach their decision.