President Rodrigo Duterte said on Monday an investigation has been ongoing on the parents of opposition Senator Antonio Trillanes IV.

In a speech in Davao City, Duterte said when Trillanes' father was with the military, her mother was also involved in deals.

"We are looking into the papers..You know that we’re investigating quietly the deals during the time of his father, also his mother was involved. And he can be very sure that all of these will come out," he said.

Earlier, Duterte accused Trillanes' mother Estelita of being a supplier for the Philippine Navy even if her husband was a Navy officer. He has accused of possible conflict of interest.

Trillanes, a stauch critic of the President, has denied the allegation.

Antonio Trillanes Sr. retired in the late 80's and passed away in 1998, while Estelita is on her 80s. Celerina Monte/DMS