March 21, 2009, was one of the bloodiest days in the history of the Oakland Police Department and California law enforcement.

It began with a trifle: Two traffic officers, Sergeant Mark Dunakin and Officer John Hege, pulled over 26-year-old parolee Lovelle Mixon for running a traffic light. After Dunakin radioed in Mixon's driver's license and learned it was fake, both officers approached the car with the intent of making an arrest. Mixon leaned out of his window and, according to a Board of Inquiry report, "methodically shot each officer twice." As the officers lay wounded on the sidewalk, Mixon crawled out of the window of his car, stood over them and shot each in the back.

Over the next two hours, roughly two hundred officers from several police agencies tore through East Oakland on a manhunt. The magnitude of the response and the absence of OPD brass from the field for ninety minutes would prove critical in shaping the remarkable carnage that followed — three more people killed and two seriously wounded. The lack of senior personnel led to a situation where, as the Board of Inquiry put it, "many responders self-assign[ed] their own activity."

At a moment when OPD's response needed to be orderly and focused, officers operated without supervision and on their own initiative. One of those officers was Sergeant Patrick Gonzales.

Gonzales would emerge from the day's dramatic violence as a department hero; some colleagues nicknamed him "Audie Murphy," after the most decorated American soldier of World War II. But to many in the black and Latino neighborhoods Gonzales polices today, he has long been known as something else: a loose cannon.

During Gonzales' thirteen-year career he has shot four suspects, three fatally. "He's left a trail of victims in his wake," said Cathy King, the mother of one of Gonzales' shooting victims. "But he's [considered] a valued member of the police department."

Multiple lawsuits alleging wrongful death, excessive force, illegal searches, and racial profiling incidents involving Gonzales have resulted in at least $3.6 million paid by the city in settlement money. Law enforcement experts say he fits the profile of the "bad apple" — a relatively small cadre of cops in OPD that are responsible for most of the allegations of brutality that plague the department's relationship with the city's communities of color. And the Board of Inquiry report on the bloody events of March 21, 2009, places significant blame for the carnage on Gonzales' decisions.

Yet, Gonzales has been consistently promoted and deployed into sensitive situations throughout his career, and without public outcry. That's because few know about either his record or his promotions. His extensive personnel file is today off-limits to the public, thanks to a dramatic rollback in the transparency of law enforcement records following a California Supreme Court ruling five years ago. The 2006 decision, in Copley Press v. Superior Court of San Diego, effectively classified all records of individual law enforcement officers, even those employed by contractors.

The arc of Gonzales' career, from a patrol officer in the Eastlake neighborhood to a sergeant on the SWAT team at the heart of one of OPD's darkest days, tells the story of a department's broken accountability system, now pushed behind a wall of secrecy.

Copley was the climax of a decades-long battle between California law enforcement unions and civil liberties advocates. During the latter part of the 20th century, many cities around the state created independent review boards to investigate complaints of police misconduct. These boards became the primary vehicle for communities to hold both individual officers and departments accountable for their interactions with residents.

In 2003, Copley Press, which published the San Diego Union Tribune, sued San Diego County to gain access to an appeals hearing for a sheriff's deputy facing termination. The suit wound its way up to the state Supreme Court, which rejected the publisher's demands. Subsequent interpretations of the ruling by cities across the state led to the wholesale redaction of identifying information for police misconduct complaints filed with watchdog agencies. According to the ruling, an officer's disciplinary information may not be released by either the department or an independent review body, citing a police officer's right to privacy.

"They've been relentless over the past 25 years to create a tool for law enforcement agencies to work without public scrutiny," Tom Newton, executive director of the California Newspaper Publishers Association, said of police unions. "With Copley, they hit the jackpot."

In an investigation involving several California police departments with varying transparency policies, Colorlines.com and the Investigative Fund of the Nation Institute found that the Copley ruling had its greatest impact on cities like Oakland, where community activism and federal intervention had prompted the department to provide unique levels of transparency about individual officers. In cities like Fresno, on the other hand, where departments had long invoked state law to shield files, Copley simply gave further legal justification to keep records secret until they're pried loose by litigation.

"It's a huge backtrack in oversight," noted former ACLU-Northern California police practices expert Mark Schlosberg. "In the long term, [Copley] is going to be really detrimental."

The bloody climax of the hunt for Lovelle Mixon offers a window into that long term.

Oakland police found Mixon hiding at his sister's apartment in East Oakland. When members of the SWAT team arrived, they cobbled together an impromptu entry team, led by Gonzales.