"They were not interested in the truth," Villanueva said of the researchers from the Santa Monica-based nonprofit RAND Corporation.
For years, the Sheriff's Department has been accused of allowing secret, deputy-only gangs within its stations throughout the county that encourage aggressive, on-the-job behavior.
In 2019, the county commissioned the RAND Corporation to look into the existence of these groups and how to deal with them. RAND's report was released earlier this month, and found that the deputy gangs still exist, are divisive to the department and that the department's leadership needs to do a better job discouraging deputies from joining them.
Villanueva said of the reports 37 recommendations for the department, 30 were already being implemented and the other seven are currently being considered.
Maxine Waters calls for federal investigation into sheriff's deputy 'gangs'
But the sheriff added that when it comes to cliques or groups in the department, he can't just outlaw them.
"If a subgroup of any set of employees engages in misconduct, that is when I, as an employer, can intervene," Villanueva said. "They're (RAND researchers) claiming that we can just ban groups outright. Well, that is not constitutionally permissible."
Villanueva has been at odds with the L.A. County Board of Supervisors since he was first elected in 2018, and the foundation of his argument against the RAND report is that it is just another attempt by the board to smear his reputation.
"My boss is the people of Los Angeles County, not the Board of Supervisors, and that is something they cannot stomach," said Villanueva. "Shame on you, Supervisor Hilda Solis."
Solis declined to talk with Eyewitness News about the sheriff's allegations. The county board, though, has issued a subpoena to Villanueva to appear Thursday before the Civilian Oversight Commission and it's nine members appointed by the board, in part to further probe deputy gangs.
The sheriff said he will not attend..
"That is not a deliberative body. That's a kangaroo court," Villanueva said. "Their entire role is to discredit the sheriff's department."