Barry Gilton and Lupe Mercado of San Francisco have been formally charged with the murder of 22-year-old Calvin Sneed, an alleged gang member who had reportedly been pimping out their 17-year-old daughter in North Hollywood.

The couple tracked their daughter down after she ran away from home, and learned she had been prostituting for Sneed. Police say the two tried unsuccessfully to kill Sneed one week before he was shot to death inside his Toyota Camry in San Francisco.

Gilton, 38, and Mercado, 37, maintain their innocence, but Gilton's lawyer, Eric Safire, said the pair had been stymied in their efforts to deal with Sneed through official channels. "They had gone out to local police agencies, agencies in Southern California - they had even tried talking to national organizations," Safire said. "Every place they turned to turned them away."

Prosecutors claim that, on June 4, frustration with the authorities' inaction led Gilton to fire into Sneed's car with a .40-caliber handgun, causing him to crash into another vehicle. He was pronounced dead at San Francisco General Hospital a short time later.

Mercado's attorney, Tony Tamburello, says prosecutors are basing their entire case on motive, but D.A. spokesman Alex Bastian insisted the case had been thoroughly investigated by police. "We would not charge a case unless we had a good-faith basis that we could prove the case beyond a reasonable doubt," Bastian said.

Sneed was alleged to be a member of the Nutty Block Crip gang, and was the victim of an LA drive-by last year.

Gilton and Mercado's daughter is currently in the care of relatives along with their three other children.

[photo via Shutterstock]