The Philippine Drug Enforcement Agency ( PDEA) and the Philippine National Police ( PNP) have cleared former presidential economic adviser Michael Yang of any involvement in illegal drugs, Malacanang said on Friday.

"Isn't it Michael Yang has already been cleared by PDEA and by the PNP. Isn't it they say that the Michael Yang being referred by (former Senior Supt. Eduardo) Acierto could be a different person?" said Presidential Spokesperson Salvador Panelo in a press briefing.

The Senate wants to investigate Yang after Acierto, a former officer-in-charge of the now defunct PNP Anti-Illegal Drugs Group, claimed Yang, a Chinese businessman, was allegedly involved in illegal drug trade.

Yang was one of President Rodrigo Duterte's advisers, especially when it comes to China despite being a foreigner.

Duterte earlier cleared Yang of any involvement in illegal drugs, saying that he was a businessman in Davao. If there was anyone who has link in illegal drug trade, it was Acierto, he has said.

Panelo said if the Senate would conduct an investigation, it would be within its prerogative.

"Congress has the right to investigate," he said. Celerina Monte/DMS