MAKATI CITY—Another bus explosion victim succumbed to shrapnel wounds while being treated at a Makati hospital early Wednesday morning, bringing to five the total number of fatalities in the attack.

This as authorities said Tuesday’s blast that tore through Newman Goldliner bus bore the signature of the extremist group Abu Sayyaf.

The fifth casualty was identified as Irish Teniola, a call center agent who died around 4 a.m. at the Makati Medical Center.

She succumbed to shrapnel wounds to the head and at the back of her body.

The other fatalities were Salustiano Marino, 57, an FX taxi driver; Johansson Reyes, 24, a culinary arts student; and call center agents Shrily Khristel Andes Hausena and Jhonlie Daquiaog, 24.

Michael Jaralve, the bus conductor who sustained wounds on his both legs, was released from the hospital. Twelve others were injured in the blast.

Investigators said a mortar shell triggered by a mobile phone similar to those used by the Abu Sayyaf led to Tuesday’s blast that ripped the bus apart.