SAN FRANCISCO (AP) - The scene repeats itself daily on city streets: a driver gets stuck bumper to bumper, blocking an intersection and preventing another car from turning left.

But authorities say that was enough to cause Edwin Ramos to unload an AK-47 assault weapon on a man and his two sons, killing them.

The deaths immediately drew public outrage, which intensified when authorities revealed that Ramos, 21, is an illegal immigrant who managed to avoid deportation despite previous brushes with the law.

The case has put San Francisco's liberal politics to the test, setting off a debate over its sanctuary law that shields undocumented immigrants from deportation.

On Wednesday, Ramos pleaded not guilty to three counts of murder in the deaths of Anthony Bologna, 49, and his sons, Michael, 20, and Matthew, 16. Bologna and his older son died in the intersection on June 22. His younger son succumbed to his injuries days later.

Shortly after that, police arrested Ramos, a native of El Salvador and reputed member of the Mara Salvatrucha gang, known as MS-13. Investigators believe he was the gunman, though two other men were seen in the car with him.

The heinousness of the deaths has put pressure on San Francisco District Attorney Kamala Harris to seek the death penalty against Ramos. Harris, who campaigned on an anti-death penalty platform and has never pursued capital punishment during her more than four years in office, has declined to say exactly how she intends to proceed.

"This case has been charged as a special circumstance case," making it eligible for the death penalty, spokeswoman Erica Derryck said. "No additional announcement has been made about this aspect of the charging."

Ramos' attorney, Robert Amparan, said his client was not the shooter. "They have the wrong person," he said.

Amparan declined to discuss details of the case, but he denied his client was involved in gang activity and said Ramos entered the country legally. Federal authorities contend Ramos is undocumented.

The victims' family learned that Ramos had been arrested at least three times before the shooting and evaded deportation, largely because of San Francisco's sanctuary status.

The policy, adopted in 1989 by the city's elected Board of Supervisors, bars local officials from cooperating with federal authorities in their efforts to deport illegal immigrants.

Officials in the juvenile offenders agency interpreted the law to also shield underage felons from deportation by refusing to report undocumented ones. Mayor Gavin Newsom said he rescinded the policy regarding juvenile offenders after learning about it in May.

The Bolognas' relatives say Ramos apparently benefited from the policy when he reportedly was convicted twice of felonies in 2003 and 2004 but never was turned over for deportation.

"All San Francisco's sanctuary ordinance has done is bring violence and death to this once-great city," said Frank Kennedy, who is married to Anthony Bologna's sister.

Kennedy called for an investigation of the sanctuary policy and demanded "prosecutions for violating the law."

Meanwhile, local and federal authorities are pointing fingers at each other over Ramos' most recent arrest before the shooting.

Ramos was arrested in late March with another man after police discovered a gun used in a double homicide in the car Ramos was driving.

The district attorney's office decided not to file charges against Ramos, and he was released April 2 even though he was in the process of being deported after his application for legal residence was denied, according to the U.S. Immigration and Customs Enforcement.

San Francisco Sheriff's Department spokesman Eileen Hirst said jail officials faxed ICE on March 30 asking if Ramos should remain jailed. Ramos was freed after Hirst said immigration officials didn't respond.

ICE spokesman Timothy Counts said his agency did not receive word of Ramos' arrest in March. He said the only communication received about Ramos was an "electronic message" from the sheriff's department three hours after his release.

The case has garnered national attention, leading U.S. Rep. Tom Tancredo, R-Colo., and an anti-immigration group called Californians for Population Stabilization to ask the U.S. Department of Justice to take over, alleging San Francisco authorities have mishandled it.

"Because San Francisco's political leaders have already demonstrated their willingness to act in flagrant violation of federal law, I do not believe that local judicial institutions can be trusted to fairly try the case or mete out an appropriate punishment," Tancredo said in a letter sent Tuesday to U.S. Attorney General Michael Mukasey.

Justice Department spokesman Charles Miller said he was unaware of the case and the congressman's request. Miller said the attorney general routinely responds privately to such requests.

Diana Hull, president of Californians for Population Stabilization, called on about a dozen cities nationwide with similar sanctuary policies to end those programs.

"We need to remember always that a death-dealing policy like `sanctuary' hides behind the false mantle of compassion," Hull said.

Nathan Ballard, a spokesman for San Francisco's mayor, said city officials were wrong to shield undocumented, juvenile felons from federal immigration authorities.

"The sanctuary program was never intended to shield felons," Ballard said. "The policy was inappropriate."

However, Newsom "still supports the worthwhile aims of denying the federal government" assistance in deporting otherwise law-abiding undocumented residents, he said.