MANILA - President Rodrigo Duterte said he has "records" of Sen. Leila de Lima's alleged misdeeds, but he would pace their release to the 70's soul classic "Killing Me Softly."

In an interview with reporters on Thursday, Duterte was asked if he had evidence against De Lima, who will mount a Senate investigation on the hundreds of deaths linked to his anti-drug campaign.

"Yes, I have already, pero killing me softly," Duterte said, before humming a verse from the Roberta Flack song.

"She's an immoral person. You wait. May tatlong record pa. Ipasok ko muna yung isa. [There are three more records. I will put in one first]," he said.

Duterte blasted De Lima for having an "illicit affair" with her driver, whom he also accused of collecting money from drug lords detained at the national penitentiary.

De Lima said the President's attack was an "abuse and misuse of executive power" and warned that her fate could befall "anyone who does not bow to the wishes of the President."

The fiery exchanges betrayed a cordial encounter between the two public officials last month, when Duterte shook De Lima's hand at the Batasang Pambansa before he delivered his first State of the Nation Address (SONA).