A Petaluma man at the center of a May 3 shootout has been indicted by a federal grand jury on new charges, accusing him of trying to kill three federal agents wounded in the pre-dawn raid at his home.

Victor Flores, 20, also known by his South San Francisco C Street gang moniker "Little Creeper," will make his initial appearance on the attempted murder charges in federal court today, officials said.

The indictment marks the first time federal officials have formally accused Flores of firing the shots that wounded three U.S. Immigration and Customs Enforcement agents. One injured agent has returned to full-time duty while the other two agents are still recovering, officials said Thursday.

Flores' father, also named Victor Flores, also took up a gun in the chaos of that day, though he has not been charged. Officials declined to say if he had been cleared of wrongdoing.

"I can neither confirm nor deny that there are any other continuing investigations," said Jack Gillund, spokesman for the U.S. Attorney's Office.

The younger Flores has been in custody since the May 3 sweep, when federal authorities rounded up 13 suspected South San Francisco gang members indicted for a host of violent crimes uncovered during an investigation into the December 2010 slaying of three rival gang members. Six other suspects already were in custody at the time of the raids.

Flores lived with his parents and younger brother in a home in Petaluma, one of 11 sites targeted that day in raids by federal and local law enforcement officers armed with heavy weapons and combat gear.

Dozens of law enforcement officers converged on the McNeil Avenue house shortly after 4 a.m., setting off an explosion and igniting a barrage of gunfire that left three ICE agents wounded.

Flores' father said he and his son both armed themselves with hunting guns after hearing the explosion and shouting, believing that someone was attacking his wife as she returned home from her night job at the San Francisco airport.

The family had moved to the rental house about seven months earlier to escape gang violence after someone fired bullets at their 14-year-old son and his friend near the Floreses' home in South San Francisco. A South San Francisco police officer later said authorities believed the pair was targeted in retaliation for the earlier triple homicide.

Victor Flores is one of four men suspected in the Dec. 22, 2010, triple homicide, which also left three wounded, according to the April 24 grand jury indictment. He faces a possible death sentence if convicted on those charges.

A superceding 33-count indictment made public this week accuses Flores of trying to kill three ICE agents during the raid on his home. If convicted, each count of attempted murder could earn Flores 20 years in federal prison, authorities said.

Flores also was indicted for allegedly using a firearm during a violent crime, which carries a maximum life sentence, federal officials said.

The indictment does not specify the type of firearm used, the degree of injury inflicted or any other identifying information. Authorities earlier said the agents faced "a barrage of gunfire from an assault rifle" when they entered the house.

The elder Flores' wife, Ana Flores, said by phone Thursday that they remained uncertain about her husband's status as a suspect. They are staying with another family in the wake of their rental home's destruction, she said.