At least 10 people, mostly leaders or supporters of politicians, have been killed since the start of the election period in Masbate.
Ovilla was placed on floating status, and replaced by Superintendent Vic Deuna, a former intelligence officer.
Bicol police director Robert Delfin said he will send additional policemen to Masbate and effect a reshuffle of partisan police officers.
The Commission on Elections has tagged Masbate as one of the poll hot spots in the region.
In the recent killing, the victim was a certain Virgilio Zabala, a supporter of a mayoral candidate in Cawayan, Masbate. The provincial jail warden is being hunted for the slay.  Celso Amo