The county commission's move makes it the latest group to support the sheriff in the battle over a secret list of 300 problematic deputies whose history of misconduct could damage their credibility if they are ever called to testify in criminal cases.
The American Civil Liberties Union and other organizations have already endorsed in court briefs McDonnell's effort to reveal the information, which is facing a legal challenge by the deputies' union.
The Sheriff Civilian Oversight Commission, created last year to increase accountability, voted 5 to 2 to approve a resolution to support the sheriff's disclosure effort.
The commission, led by former federal judge Robert C. Bonner, approved a resolution that said both the Sheriff's Department and District Attorney's office have "a duty under the due process clause of the United States Constitution to provide defendants in criminal cases with evidence within their possession that is favorable to such defendants."
Bonner, who headed the Drug Enforcement Administration before joining the oversight panel, was part of a blue-ribbon commission that found a pattern of excessive force under McDonnell's predecessor.
Commissioners Lael Rubin, a former top prosecutor, and J.P. Harris, a retired sheriff's lieutenant, opposed the move.
"I vote no for the specific reason that I feel incumbent to understand and know how it is that this list got put together," Rubin said. "I would not vote no in the future if I was satisfied it was put together fairly and in compliance with the law."
Rubin, who as a prosecutor handled the issue of so-called Brady disclosure, said she wants to know from the department more details about what led names to be on the list.
Harris said he agreed with Rubin that he needed a better understanding of the list's construction before endorsing the sheriff's effort.
The Assn. for Los Angeles Deputy Sheriffs has sued the department over the disclosure, saying it would violate peace officer confidentiality laws and draw unfair scrutiny of deputies whose mistakes might have happened long ago.
A Superior Court judge agreed in January that providing the list would violate state law, but said the department could turn over the names of problem deputies when there's a pending case in which that officer might testify. Last month, a two-judge appellate court panel granted the union's request to put a temporary hold on any transmission of names, even in pending cases.
Activists on Thursday told the oversight commission that they needed to back the sheriff's efforts and that there should be more transparency.
Kim McGill of the Youth Justice Coalition told the oversight commission that it should push the district attorney to not allow these deputies any authority in court given their histories. The commission, she said, needs to encourage all police agencies across L.A. County to make a similar disclosure.
Helen Jones told the commission that she received a $2-million settlement from the county related to a relative's jailhouse death and yet the deputies involved are now at sheriff's stations across the county.
Under the 1963 U.S. Supreme Court ruling in Brady vs. Maryland, prosecutors are obligated to alert defendants to any evidence that could aid the defense. That evidence includes information that could undermine an officer's credibility. Not doing so could result in wrongful convictions.
The ACLU filed a friend-of-the-court brief early this month asking the appeals court to reject the Assn. for Los Angeles Deputy Sheriffs' request that none of the names of problem deputies be sent to prosecutors.
The department warned about 300 deputies in October that their personnel files contained evidence of "moral turpitude." The letters said such acts could include accepting bribes or gifts, misappropriating property, tampering with evidence, lying, obstructing investigations, falsifying records, using unreasonable force, discriminatory harassment and family violence. Sheriff's officials said it was possible that some of the offenses didn't apply to any current deputies on the department.
The targeted group represents about 3% of the department's roughly 9,100 deputies.
In the letters, the department said the list would include only deputies found guilty of wrongdoing by internal investigators. The agency would send only the deputies' names, not their entire personnel files, the letters said.
Los Angeles County Dist. Atty. Jackie Lacey office has said her offiice does not obtain lists of problem officers from police agencies. Her office so far has not taken a position on the legal challenge
But last month, one of her deputy district attorneys filed a declaration in the sheriff's union's favor stating that Lacey's office "actively declines to accept information" from officer personnel files without the permission of the officer. But in an interview with The Times, Lacey distanced herself from Deputy Dist. Atty. Jason Lustig's declaration, saying it wasn't her position.