A PHILIPPINE lawmaker on Sunday said her grave threat complaint against ex-President Rodrigo R. Duterte would test the country’s justice system and could hopefully pave the way for investigations of his anti-illegal drug campaign.

“The case will serve as a litmus test of the justice system in this country,” Party-list Rep. France L. Castro said in a Viber chat. “This will start the ball rolling to investigate Duterte.”

Harry L. Roque, Mr. Duterte’s spokesman, did not immediately reply to a Viber message seeking comment.

Ms. Castro last week filed a criminal complaint against Mr. Duterte after he allegedly threatened to kill her in an SMNI television interview on Oct. 11.

The ex-President “called my name multiple times and made grave threats to kill me and made me immensely fearful for my life, safety and security,” Ms. Castro said in the complaint before the Quezon City Prosecutor’s Office.

Mr. Duterte said he had told his daughter, Vice-President Sara Duterte-Carpio, to say that she would use her intelligence funds to kill Maoists in Congress including Ms. Castro.

“Your first target in your intelligence fund is France, the communists, whom you want to kill,” he said in Filipino.

Ms. Castro, a member of the minority at the House of Representatives, had criticized P650 million in confidential funds of Ms. Duterte-Carpio as vice president and Education secretary, noting that these agencies do not have intelligence and security mandates.

Ms. Duterte-Carpio had sought P500 million in confidential funds for her office and another P150 million for the Education department.

Mr. Duterte must answer for his unlawful and threatening remarks, said Ephraim B. Cortez, president of the National Union of Peoples’ Lawyers.

“Now that he is an ex-President who does not have any authority to dish out official favors, he may not simply get away this time,” he said in a Facebook Messenger chat.

“Duterte is no longer immune from suits,” Rogelio Alicor L. Panao, who teaches political science at the University of the Philippines, said via telephone.

But he could still use his popularity to get escape punishment, Arjan P. Aguirre, a political science professor at the Ateneo De Manila University, said in a Messegner chat.

“We can expect that Duterte won’t cooperate or perhaps may even use this to mount his own media stint by countering Rep. Castro with his populist tirades,” he said. “He knows that he is popular and will definitely use this popularity to protect himself.”

Mr. Cortez said said Mr. Duterte’s political allies appear to have crumbled especially with the House of Representatives stripping her of her confidential funds next year.

Congressmen on Oct. 10 stripped several agencies including the Office of the Vice President and Education department of their confidential funds, transferring P1.23 billion worth of these budgets to security agencies amid worsening tensions with China.

President Ferdinand R. Marcos, Jr.  in July said his government would not cooperate with the International Criminal Court’s (ICC) investigation of Mr. Duterte’s war on drugs. 

The Philippine government estimates that at least 6,117 suspected drug dealers were killed in police operations under the Duterte administration. Human rights groups say as many as 30,000 suspects died. — Beatriz Marie D. Cruz