SANFORD -- Defense lawyers are free to subpoena Trayvon Martin’s school records and social media accounts, a judge ruled Friday, setting the stage for a show-down between a man facing life in prison and new media companies that are unlikely to turn over records without a fight.

The decision was a disappointment for the slain teenager’s family, who believe digging into a homicide victim’s past is tantamount to blaming a rape victim for wearing too short a skirt.

Defense attorney Mark O’Mara asked Seminole County Circuit Judge Debra Nelson to let him explore the validity of Twitter and Facebook screenshots — dug up by conservative bloggers — that portray Trayvon in a negative light. Acknowledging that he does not know whether the Facebook and Twitter material is authentic, O’Mara said the social media accounts attributed to Trayvon showed he attended and posted videos of mixed martial arts fights.

Other social media screen shots widely circulated on the web suggested Trayvon got into a fight at school and maybe even sold marijuana to his friends. Critics believe he was up to no good on the night he walked home from a 7-Eleven and wound up in a fatal encounter with an armed neighborhood watch volunteer, and believe Trayvon’s social-media posts could offer clues as to whether he had nefarious plans.

“Let them have [the subpoena],” the judge said. “Let them argue with Twitter.”

According to case law, when a defendant claims self defense the victim’s propensity for violence is relevant, even if the defendant didn’t know anything about the victim’s history, the judge said.

George Zimmerman, 29, is charged with second-degree murder for the Feb. 26 killing of Trayvon, who was unarmed. Zimmerman claims the teen attacked him, and he was forced to shoot in self-defense.

Prosecutors, who subpoenaed and got similar evidence about Zimmerman, did not object. The family of the unarmed Miami Gardens teenager was disappointed, and called the decision a terrible precedent.

“Trayvon Martin died because George Zimmerman profiled him as a young punk under the guise of protecting his neighborhood. Now Trayvon Martin is being profiled again posthumously as an MMA- loving violent thug under the guise of pursuing justice,” said attorney Benjamin Crump, a lawyer for Trayvon’s parents, who led the charge for Zimmerman to be arrested. “This has to stop. Profiling, like racism and sexism, has no place in the criminal justice system.”

He added that there was nothing in Trayvon’s school records that would “justify murder.”

But getting a green light for subpoenas was only the start. O’Mara acknowledged that the social-media companies are unlikely to give up so quickly.

Facebook lawyers have already notified attorneys in the case in writing that they believe federal law does not allow the company to disclose user-account information. Twitter is locked in a court battle with the New York Police Department over that agency’s subpoena of tweets belonging to an Occupy Wall Street protester.

An appellate decision in that case is expected in November, O’Mara said. To avoid being found in contempt, Twitter has delivered the information to the case judge under seal.

“They are a multinational company with billions of dollars — I’m not prepared at all to take on Facebook and Twitter. I’m just hoping they understand that we have a discovery rule that says that we get information that will help prove our client was innocent,” O’Mara told reporters afterward. “If it’s there, we at least get to see if it’s there.”