Metro Manila (CNN Philippines, December 25) — Senator Antonio Trillanes, a staunch critic of the Duterte family, called Vice Mayor Paolo Duterte's resignation from his post "pure BS."

"Delicadeza, seriously? Pinatulan nga niya yung anak niya [He fought with his daughter] publicly sa Facebook, tapos delicadeza? Besides, he has already been cleared months ago by Gordon's committee de abswelto. So, that's pure BS," Trillanes said in a statement Sunday.

Duterte tendered his resignation on Christmas Day. In his resignation letter for his sister and superior, Davao City Mayor Sara Duterte, Paolo mentioned the importance of "delicadeza," alongside his social media squabble with his daughter, Isabelle.

READ: Davao City Vice Mayor Paolo Duterte resigns

In September, Trillanes and Vice Mayor Duterte figured over the latter's alleged involvement in the drug trade. The Vice Mayor and the President's son-in-law Atty. Manases Carpio were summoned to the Senate probe over the ₱6.4 billion worth of methampetamine hydochloride (shabu) hauled with ease into the country last May 24.

Senate Blue Ribbon Committee chair Richard Gordon then called Trillanes' accusations as "editorializing." The two senators also got into a heated exchange after Trillanes called the panel a "committee de abswelto" for Gordon's refusal to summon Carpio and Duterte.

But Trillanes, in his statement, said Paolo is just evading probes into his involvement.

"He is probably just preempting the numerous investigations against him by the Ombudsman. Also, he most likely needs more time to focus on managing his multi-billion peso businesses," Trillanes' statement added.

The senator earlier accused Paolo of being involved in a Chinese drug triad group. Paolo repeatedly denied Trillanes' allegations, which included a tattoo on his back to represent his membership.

READ: Trillanes: Paolo Duterte a Chinese drug triad member

Trillanes said he believes Paolo is behind the illegal importation.

READ: Ombudsman probes ₱6.4-B shabu smuggling

Paolo got involved with the Customs issue after broker Mark Taguba claimed he gave ₱5 million to the Davao Group to meet with him. Taguba has since retracted his statements, clearing the vice mayor and Duterte's son-in-law of links to the drug trade.