The scene repeats itself every day on city streets: A driver gets stuck bumper-to-bumper, blocking the intersection and another car's ability to complete a left turn.

Authorities say that was enough to prompt Edwin Ramos to unload an AK47 assault weapon on a man and his two sons, killing all three.

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

The case has put San Francisco's liberal politics to the test, igniting a nationwide debate over its sanctuary law that shields undocumented immigrants from deportation and putting pressure on the district attorney to break her anti-death penalty pledge.

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, a supervisor at a San Mateo grocery store and a youth sports coach, and his older son died in the intersection in the city's Excelsior district on June 22. His younger son succumbed to his injuries a couple days later.

Shortly after that, police arrested Ramos, an El Salvador native and a reputed member of the notorious Mara Salvatrucha gang, known as MS-13. Investigators believe he was the gunman, although two other men were seen in the gray Chrysler 300M with him.

The heinousness of the crime has put considerable 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 directly address how she intends to proceed.

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

Outside court Wednesday, 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 also denied that his client was involved in "gang activities" and said that Ramos "entered the country legally," even though federal officials contend Ramos is undocumented.

The victims' family learned that Ramos had been arrested at least three times prior to the shooting and evaded deportation, largely as a result of San Francisco's self-imposed sanctuary status.

The policy, adopted in 1989 by the city's elected Board of Supervisors, barred 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 their undocumented status. Mayor Gavin Newsom said he rescinded the nearly two-decade policy regarding juvenile offenders after learning about it in May.

Bologna family members say Ramos apparently benefited from this policy for juveniles when he reportedly was convicted twice of felonies in 2003 and 2004 but never was turned over for deportation.

The case has since garnered national attention, prompting Republican Rep. Tom Tancredo of Colorado and an anti-immigration group called Californians for Population Stabilization to ask the U.S. Department of Justice to take over because of San Francisco's alleged mishandling of the case.

"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," Trancredo said in a letter sent Tuesday to U.S. Attorney General Michael Mukasey.

Diana Hull, president of the anti-immigration group, also called on about a dozen cities nationwide who have 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.

Charles Miller, a Justice Department spokesman, said he was unaware of the San Francisco case or the congressman's request. Miller said it's routine for the attorney general to respond privately to requests such as Tancredo's.

Nathan Ballard, a spokesman for San Francisco Mayor Gavin Newsom, 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, Ballard said.