As Los Angeles officials sought to mend fractured community relations Thursday by joining a march denouncing the police confrontation at a May Day rally, the ACLU filed a scathing petition asking a federal judge to consider extending a consent decree.

The strongly worded petition - which calls for a special hearing with the judge - argues the violent police action earlier this month exposes an entrenched, aggressive culture despite years of hard work to turn the department around.

"The LAPD's apparently deliberate and widespread use of excessive force on May 1 suggests an institution permissive of excessive force - a suggestion that is all too familiar regarding the LAPD," says the petition filed by the American Civil Liberties Union and constitutional lawyer Erwin Chemerinsky.

The federal consent decree was imposed on the LAPD in 2001 after the Rampart scandal revealed widespread police abuse and corruption. The decree required the department to rid itself of the abuse, but it was extended in 2006 due to a lack of compliance.

The decree is now set to expire in 2009. In the months before the melee at MacArthur Park, the LAPD had appeared to be in a good position to have it finally lifted, largely due to reforms implemented by Police Chief William Bratton.

But the ACLU petition argues that further change is still needed in the department.

"The egregiousness of the violations at MacArthur Park, the methodical manner in which they were committed, and the number of officers involved raise questions as to the extent of the Department's progress and the reach of the reforms so far implemented," it said.

In its request for a hearing, the ACLU said the judge should consider requiring reforms similar to those the consent decree imposed on the department's gang units - including caps on the amount of time an officer can serve in a particular unit.

Mayor Antonio Villaraigosa, who was on a trade mission to Central America and Mexico when the May Day rally occurred, joined thousands of marchers Thursday.

Beginning at a town hall-style meeting at Immanuel Presbyterian Church, an estimated 3,000 marchers followed a 10-block procession to MacArthur Park.

"We acknowledge that what happened on May 1 is wrong, that we have to get to the bottom of it, that we've got to investigate, that we have to have an open and transparent investigation that ensures that justice is realized," Villaraigosa told the crowd.

LAPD officers in charge of crowd control Thursday handed out yellow fliers in English, Spanish and Korean, telling marchers the police are committed to respecting and protecting people's rights to assemble and speak freely.

Bratton, who apologized for his officers' actions and demoted two top-ranking officers in charge that day, was also on hand Thursday.

Some marchers called for Bratton's resignation as they arrived in MacArthur Park, but Bratton took it in stride, shaking hands with marchers and hugging babies.

"MacArthur Park was an exception in the city and we want to keep it this way," he told reporters.

But the chief faces a lot of questions in the weeks ahead.

The ACLU petition follows concerns expressed earlier this week by Michael G. Cherkasky, the independent monitor of the consent decree, who noted the melee in a quarterly report.

"While the details of exactly what occurred and why have yet to be determined, the police actions that occurred on May 1, 2007, have raised many questions," he said, adding that he will continue to monitor the investigation and how it unfolds.

The immigrants rights May Day protest ended with baton-wielding police firing more than 140 rounds of rubber bullets into a crowd of protesters that included children.

"There was already fear about the police in the community," said Angelica Salas, executive director of the Coalition for Humane Immigrant Rights, a key organizer of the May Day march for immigration reform. "When they see police beating up people with children, it ... reinforces misgivings about how much the police are there to protect immigrant communities."

Three investigations of the May Day fracas have been launched, including a federal inquiry into civil rights violations. But ACLU lawyers say the LAPD culture is so troubling, systematic changes need to be taken.

"This is precisely the sort of action of police misconduct that the decree was designed to prevent," said Mark Rosenbaum, legal director for the ACLU of Southern California. "What is riding on this is the effect and integrity of the decree." [MORE]

• Pictured above: Mayor Antonio Villaraigosa and California Assembly Speaker Fabian Nunez join activists in a rally, march, and vigil marking the May 1 melee in MacArthur Park in Los Angeles Thursday.