Rafael Perez told U.S. District Judge Christina Snyder he fabricated a story about a shooting that left a man paralyzed and testified falsely at the victim's trial.
Perez and his partner shot 19-year-old illegal immigrant Javier Francisco Ovando during a 1996 arrest. The two officers claimed at the time that Ovando attacked them first, reports CBS News' Steve Futterman. Ovando was unarmed and the officers planted a gun on him, said U.S Attorney John Gordon.
"After they shot Ovando, they covered up the circumstances, fabricated a story and then presented it in court and got the guy 23 years that he didn't deserve," said Gordon.
Perez was expected to be sentenced to two years in the federal case.
The shooting of Ovando was among serious crimes revealed by a probe of a Los Angeles police anti-gang unit working the city's tough Rampart area. The scandal overturned dozens of criminal convictions.
Ovando received a $15 million settlement with the City of Los Angeles.
Perez, 34, who has already served time in state custody, reached a deal with federal prosecutors to admit one count of conspiracy to violate Ovando's civil rights and one count of possessing a firearm with an obliterated serial number.
"At this time I want to have a resolution to all of this," Perez told the judge Monday.
The judge said she was inclined to accept his plea but would not make it formal until after she reads a report on his background, crimes, financial status and personal history.
Perez will remain free on $50,000 bond until sentencing on March 18. Under the deal Perez will serve two years in federal prison and three years on supervised release.
U.S. Attorney John S. Gordon said he wasn't prepared to comment on whether Perez would be testifying against others.
Perez was freed from state prison in July after serving three years for stealing cocaine from a police evidence locker. In exchange for a lighter sentence in that case, he cooperated with an investigation of the now-defunct Rampart gang unit.
Perez was granted immunity from state prosecution for his testimony but not from federal prosecutors. He implicated about 70 officers, forcing dismissal of more than 100 criminal convictions tainted by those allegations.
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