Malacanang expressed belief on Tuesday President Rodrigo Duterte's remarks raising "suspicion" on the alleged link of slain Tanauan Mayor Antonio Halili would not affect investigation by the authorities.

In a press briefing, Presidential Spokesperson Harry Roque said the government has vowed to conduct a thorough investigation into Halili's killing.

"I think it won't ( affect the probe) because he said 'suspicion' while the investigation has not yet started," he said when asked that Duterte's statement regarding Halili might affect the investigation on the case.

"The promise of the government is to have an extensive investigation, in-depth investigation to know who was really behind the killing of Mayor Halili," he said.

Duterte, in a speech in Maasin City, Southern Leyte on Monday night, said Halili's shame campaign appeared to be just a front on his alleged involvement on illegal drugs.

Halili was killed by an unidentified sniper during a flag-raising ceremony in front of the Tanauan City Hall on Monday morning.

Roque said the Palace was alarmed of the killings, such as Halili's case, saying these should not be happening.

"What we are alarmed at is the fact that it was broad daylight and in such a public manner. So yes we share the alarm and that’s why we have promised that we will leave no stones unturned in the investigation," he said.

Some lawmakers have said Halili's murder shows there is a culture of impunity in the country under the Duterte administration. Celerina Monte/DMS