Senate Minority Leader Franklin Drilon on Tuesday said Congress must investigate the use of unauthorized vaccines in the country, even with the Presidential Security Group ordered to keep mum on the matter by President Rodrigo Duterte.

“But to investigate in aid of legislation is also a valid exercise of legislative power. There is no preventing Congress from eliciting information in aid of legislation from other resource persons. Congress can exact information on matters that can help it craft better legislation,” said Drilon as Duterte on Monday warned the Congress of a “little crisis” if PSG is probed by lawmakers.

“I will not elaborate on it but do not force my hand to meddle into this affair because maybe I will not, I am not so keen about allowing [PSG chief Brigadier General Jesus] Durante and the rest of the PSG to testify, ” said Duterte in a televised address on Monday.

“The Senate should continue with the hearing, especially in the light of the revelation that 100,000 POGO workers were inoculated in the country. That is illegal. In aid of legislation, the Senate must elicit information from other sources on how to strengthen the FDA and the Bureau of Customs to prevent similar episodes in the future,” said Drilon.