Proposition 89, adopted in 1988, allows the governor to single-handedly reverse parole decisions in murder cases only.
Parole board staff has 120 days to review the case for any errors of law or fact in its decision, said Luis Patino of the California Department of Corrections and Rehabilitation.
Protopappas' attorney, Rich Pfeiffer, was unavailable for comment Wednesday. In March, after his client won his appeal to get a new parole hearing, Pfeiffer said he expected the governor to reverse the board's decision, and is ready to fight it.
Protopappas was convicted in 1984 of three counts of second-degree murder. In late 1982 and early 1983, Protopappas killed Kim Andreassen, 23, Cathryn Jones, 31, and Patricia Craven, 13, by giving them fatal doses of a general anesthetic in his Costa Mesa dentist office.
He was using narcotics heavily at the time and he wasn't licensed to administer the anesthetic. In the years following his conviction, Protopappas continued to deflect responsibility, Pfeiffer acknowledged. But more recently, the former dentist accepted responsibility, has been sober and has plans for his life outside of prison, Pfeiffer said.
A three-judge panel in March ruled that the state parole board was wrong to reject Protopappas' release in 2008 because there was no evidence that he remains a danger to society.