Former president Rodrigo Duterte sent a birthday message to Senator Ronald “Bato” dela Rosa, who marked his 64th birthday on Wednesday, 21 January, according to Vice President Sara Duterte.

Sara Duterte said she relayed the occasion to her father during a visit at The Hague, Netherlands, where the former president is detained at the International Criminal Court (ICC).

“Kanina nag-usap kami ni Pangulong Duterte at sinabi ko sa kanya na birthday ni Senator Bato Dela Rosa. Ay, oo nga pala kahapon. Sabi ko, message kay Senator Bato Dela Rosa. Sabi niya, ‘happy birthday, Senator Bato. Magpakatigas ka na parang Bato.’ Ito ang kanyang wish,” Duterte said in an ambush interview on 22 January.

The vice president has been visiting her father at the ICC detention center, where he is facing charges of crimes against humanity over alleged extrajudicial killings linked to his administration’s war on drugs.

Dela Rosa, a long-time ally of the Duterte family, previously served as chief of the Philippine National Police and was the primary implementer of the former administration’s anti-drug campaign.

The senator has been absent from Senate plenary sessions since 11 November, after Ombudsman Jesus Crispin Remulla said the ICC had issued an arrest warrant against the former police chief.

Dela Rosa has been tagged as one of the alleged co-perpetrators in the crimes against humanity case against Duterte, who has been detained in The Hague since March last year.