SAN FRANCISCO (CBS SF) — A former San Francisco police officer who testified against two colleagues in a federal corruption trial received the comparatively light sentence of 12 months in prison Thursday morning.

Reynaldo Vargas’s testimony was instrumental in the convictions of Sgt. Ian Furminger and Officer Edmond Robles, who each received sentences of more than three years earlier this year, U.S. District Judge Charles Breyer acknowledged at Thursday’s sentencing.

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Vargas spoke before his sentencing Thursday to once again acknowledge his guilt.

“If I’m going to go forward, I have to acknowledge everything I’ve done in the past and accept responsibility for that,” Vargas said.

He said he came to the realization he will never again be a police officer and has taken steps to pursue a new career, including taking college classes in math and science.

Vargas was fired from the department for falsifying time cards in 2012. Furminger and Robles both resigned shortly after their convictions.

Federal prosecutor John Hemann said the difficulties Vargas faced in agreeing to testify against his former colleagues should not be underestimated and he praised the extent of his cooperation.

“He did everything we asked him to do, he did so openly and willingly and he told us things we did not know,” Hemann said.

The three officers were charged with the theft of money and property from suspected drug dealers during search operations in San Francisco and Newark in 2009. Vargas and Robles were partners doing undercover drug investigations in San Francisco’s Mission District.

Vargas pleaded guilty shortly before their trial started to charges of conspiracy to distribute drugs, distribution of marijuana, conspiracy to commit theft, and theft, while agreeing to testify against the other officers.

During the trial, he described the thefts in detail, including of thousands of dollars from a suspected drug dealer living in a residential hotel in the Mission and another in the Potrero Hill neighborhood.

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While assisting the U.S. Drug Enforcement Administration in a raid on a Newark property, Vargas himself uncovered $30,000 buried in the backyard and he, Furminger and Robles split the cash three ways, Vargas testified.

The jury found Furminger guilty of conspiracy to violate civil rights, two counts of wire fraud and conspiracy to steal from a federally funded program, namely, the Police Department. Robles was convicted of the same charges, as well as an additional count of theft.

Breyer handed Furminger a stiffer sentence of three years and five months, compared to Robles’s three years and three months, since Furminger was in a position of authority over the other officers.

Breyer said he doesn’t think Vargas cooperated simply in the hopes of getting a better deal, but honestly sought to come to terms with the crimes he had committed.

“This is the final chapter in a very sad story for the San Francisco Police Department,” Breyer said today. “Your honest cooperation was crucial, essential to the successful prosecution of this case.”

But he said the implications of the case make it one of the worst he’s seen in his years on the bench because it threatens the credibility of the entire criminal justice system.

Vargas was not implicated in another San Francisco police scandal that grew from a briefing by prosecutors in the case, the exchange of racist and homophobic text messages between Furminger and other officers in the department.

While that scandal has implicated current San Francisco police officers, neither Robles nor Vargas participated in the text messages released by the U.S. Attorney’s Office.

In addition to the 12-month prison sentence, Vargas will be on probation for three years following his release. He was spared a fine that could have been as much as $20,000.

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