The Philippine National Police ( PNP) said it will get to the bottom of the ambush of a mayor and his two companions in La Union on Monday, a spokesman said Tuesday.

"We will not leave any stone unturned until we get into the bottom of this case and we will be able to arrest the suspect and put them behind bars," said Chief Superintendent Benigno Durana Jr , in an ambush interview.

He said the wife of slain Sudipen municipality Mayor Alexander Boquing, Wendy Joy, will be given "enhanced security protection." "She is the remaining witness in this case," said Durana.

Durana said Boquing is not on the drug list.

Boquing's vehicle was shot at by unidentified gunmen when it was proceeding to Bangar Monday evening. PO2 Rolando Juanbe and Boni Depdepen were killed while Boquing's wife remains in a hospital. Durana said Juanbe was not a police escort but wanted a ride home

Durana said Boquing is the 11th mayor killed this year. All in all, the PNP is investigating 17 deaths, including six vice mayors. DMS