In a radio interview Monday, Villanueva said he knows LeBron cares about law enforcement and a good way to show his support would be to pitch in on the reward, which has now increased to $200,000.
The sheriff also said we need to appreciate "that respect for life goes across all professions."
It's not known whether LeBron is aware of the sheriff's challenge but the Lakers star has recently been vocal about social justice issues and has condemned police misconduct, including in the case of Breonna Taylor.
LA deputies shooting: Manhunt intensifies for gunman as reward offer grows
Meanwhile, a GoFundMe page for the two L.A. County sheriff's deputies wounded in Saturday's ambush shooting has swelled to over $300,000.
The deputies remain hospitalized but Villanueva was hopeful Monday about their prognosis.
Anyone with information regarding the suspect was encouraged to contact the Sheriff's Department's Homicide Bureau at 323-890-5500.