The brother-in-law and alleged former MS-13 gang associate of Edwin Ramos, a man accused of a triple killing in San Francisco in 2008, testified Thursday that Ramos initiated him into the gang.

Abraham Martinez, 22, testified against Ramos, 25, who is charged with fatally shooting Anthony Bologna, 48, and his sons Michael, 20, and Matthew, 16, as the family drove near Congdon and Maynard streets in the city's Excelsior District on June 22, 2008.

Prosecutors allege that Ramos shot the Bolognas after mistaking them for rival gang members and that the shooting was in retaliation for the shooting of another MS-13 gang member earlier that day.

Martinez, whose sister is married to Ramos -- although defense attorney Marla Zamora says the couple is now separated -- said Ramos was part of the 20th Street clique of MS-13.

Martinez testified that he himself became involved in the gang when he was just 9 years old through his uncles, who were MS-13 members.

About a year later, he got "jumped in" to the gang via an initiation in which three members of the gang beat up a new member for 20 seconds.

Martinez, who went by the gang name "Goofy," testified that Ramos, known in the gang as "Popeye," was one of the three members who participated in his initiation.

"They beat me up ... hitting me, kicking me" and also knocking a tooth loose, he said.

Martinez testified after the district attorney's office granted him immunity and dismissed charges against him in connection with a Mission District stabbing on June 19, 2008 -- three days before the Bologna killings.

The charges were dismissed because Martinez was indicted in 2009 on federal charges of conspiracy to racketeer for MS-13 and illegal possession and use of a firearm. He pleaded guilty and is awaiting sentencing, and has testified against other MS-13 members in the federal trial.

Martinez testified Thursday that although Ramos was initially in the 20th Street clique, he left and was "jumped in" to another MS-13 clique, Pasadena, in 2006.

Zamora, Ramos' attorney, said in her opening statements last week that her client ceased being a gang member in 2006 but remained friends with many of the gang members in the following years.

Testimony ended for the day Thursday afternoon before Zamora was able to cross-examine Martinez, but while speaking to reporters outside of court, she questioned the prosecution's use of a witness with such a questionable history.

Martinez admitted on the witness stand to the 2008 stabbing, as well as an earlier high-speed chase during which he was shot by San Francisco police and arrested.

"For someone of his character to be used as a witness, it's disgusting," Zamora said.

She said Martinez was only testifying to help reduce his sentence in the federal case.

"A rat is a rat," she said, calling his testimony "beyond snitching."

Martinez defended his actions as a member of the gang, saying he was a victim of his circumstances.

"I knew it was a bad thing, but I didn't care," he said. "It was the cards I was dealt, and I tried to play them as best I could."

Martinez's testimony will resume on Monday. The trial, which is expected to last months, is off on Fridays.

The Ramos case brought national attention to San Francisco and the city's sanctuary policy, which protected undocumented juveniles suspected of crimes from being reported to federal immigration agents.

Ramos is an illegal immigrant from El Salvador and had multiple contacts with San Francisco police as a juvenile but was not reported to U.S. Immigration and Customs Enforcement.

The city has since changed its policy.