The sentencing of George Perez, who worked at Madoff’s firm from 1991 until its collapse in 2008, came nine months after a Manhattan federal jury found him guilty and a day before the sixth anniversary of Madoff’s arrest.

U.S. District Judge Laura Taylor Swain also ordered Perez to forfeit a symbolic $19.7 billion jointly with other defendants who worked at Bernard L. Madoff Investment Securities LLC.

“He must be punished in a way that’s severe and commensurate with his crimes,” she said.

Perez, 48, was the fourth of five former employees to be sentenced following their convictions in March on all counts, including securities fraud and conspiracy in the first criminal trial over Madoff’s Ponzi scheme.

Perez told Swain he was “sad and tired,” adding: “I’m terribly sorry for the role my work played.”

Madoff is serving a 150-year prison term after pleading guilty in 2009 to running a scheme that cost investors more than an estimated $17 billion in principal.

Prosecutors said the employees knowingly propped up Madoff’s fraud by creating fake documents and backdating trades. Prosecutors said Perez developed and maintained computer programs that enabled the fraud to multiply.

The defendants have said Madoff deceived them into believing his investment advisory business was legitimate. They are expected to appeal their convictions.

Daniel Bonventre, Madoff’s former back office director, was sentenced Monday to 10 years in prison. On Tuesday, former Manager Annette Bongiorno and Computer Programmer Jerome O’Hara received six years and 2-1/2 years, respectively.

All the defendants received less prison time than requested by prosecutors, who in Perez’s case had asked for more than eight years.

Matthew Schwartz, an assistant U.S. attorney, ahead of Perez being sentenced, urged Swain to avoid issuing further light sentences for the Madoff defendants to avoid setting a precedent in future fraud cases.

“Judges will have to explain how small-time crooks in front of them were worse than the defendants in this case,” he said.

Swain nevertheless gave Perez a less-harsh sentence than prosecutors wanted, saying he was less culpable than other defendants.

Fifteen people have been convicted in connection with Madoff’s fraud. A final defendant, former Portfolio ManagerJoann Crupi, is scheduled to be sentenced next Monday.