There are ''no indications'' of suicide bombing involved in Sunday's attack on Mindanao State University (MSU) which left four dead, the Philippine National Police (PNP) said Monday.

In a press briefing, PNP spokesperson Col. Jean Fajardo said the four fatalities were Christians.

“I talked to the PD (provincial director). Since these are Christians, the mass was ongoing when this happened. In fact, four of these victims are Christians. So there are no indicators that there was suicide bombing involved in the incident,” Fajardo told reporters.

She said that of the four deaths, three were female while one was male.

Fajardo said the two persons of interest identified by the Bangsamoro police may have been involved in previous bombing incidents.

“There was no identification given to us as to the two POIs (persons of interest) but we were told that there is an indication that they are maybe a member of a certain group that was reported to have previously been involved in bombings, particularly bus bombings,” she said.

“Among those being investigated was the kind of vehicle being used by the POIs, if they went there by foot or by driving a motor. The backtracking of the CCTV footage within the peripheral areas of MSU is ongoing,” she added.

Fajardo said the investigators are still determining if the fragments of 60-millimeter mortar recovered from the incident was battery or cellphone-operated so they can identify the group behind the bombing.

She also said there is no suspension of carrying firearms in Marawi.

Fajardo said Mindanao is now on heightened alert because of the bombing incident and the holiday season.

“The security which we have organized, particularly the declaration of full alert is an offshoot of the bombing incident,” she said.

Police in the National Capitol Region have been placed under heightened alert after the Marawi bombing on Sunday.

“We have placed NCR (National Capital Region) on heightened alert again to make sure that the whole Metro Manila will still be safe and peaceful and we are anticipating travel and an increase in economic activities here,” Fajardo said. Jaspearl Tan/DMS