The Board is looking to review the legal authority of the sheriff's "truth and reconciliation" commission, which reviews disciplinary actions regarding deputy misconduct.
Without any input from the Board, the sheriff reinstated Deputy Caren Carl Mandoyan, based on the commission's recommendation.
Mandoyan, who volunteered on the sheriff's campaign, was fired amid allegations of domestic violence.
MORE: Judge rules fired LA County deputy will keep gun and badge for now
The sheriff said the existing process determining deputy misconduct is flawed.
"The guidelines were improperly imposed. The standard for false statements was wide and beyond the scope of what is legally permissible, and exculpatory information was excluded," Villanueva said.
A judge refused to honor a county request to issue an emergency order overturning Deputy Mandoyan's re-instatement. Despite that, the county refuses to pay the deputy an employee salary.
"We control the sheriff's budget and the like, and so a lot of this comes onto our plate," Supervisor Mark Ridley Thomas.
"He made the comment that we lost in court, in fact, we didn't. What the judge ruled was that there was no urgency in taking this deputy off line as it relates to returning his badge and his gun," Supervisor Kathryn Barger said.
The sheriff said his department is reviewing more than 400 disciplinary cases in which deputies were fired.
"That's a staggering amount of cases, the majority of these cases involve employees of color," Villanueva said. "All of these cases involve people who have families."
A judge plans to hear the case in June.