Related: Philippine President Admits He Should've Been "More Active" in Resolving Hostage Crisis

"Friendly fire" could have led to the death of some tourists from Hong Kong who was hostaged on Aug. 23, Justice Secretary Leila de Lima said Thursday.

"There is a big possibility that there are friendly fire," de Lima said in a press briefing. De Lima heads the Incident Investigation and Review Committee (IIRC), a multi-sectoral team that President Benigno Aquino III has directed to probe the hostage crisis.

De Lima said the results of the forensic investigation of the hijacked tourist bus "is not consistent" with the account given by bus driver Alberto Lubang.

"What is crucial is if shots were made at close range," she said.

Lubang testified that the hostage taker, dismissed policeman Rolando Mendoza, shot the victims at close range.

But de Lima said that the report presented by Philippine National Police-Scene of the Crime Operations (PNP-Soco) and the National Bureau of Investigations revealed that if Mendoza, who used an M-16 rifle, actually fired at close range, then the wounds of the victims would have been bigger.

De Lima said the forensic report is not yet complete as the IIRC is still awaiting ballistic exams from Hong Kong.

"Where did the shots came from ? (Did they came from) the hostage taker, the assault team or other teams?" She also noted that IIRC members doubt that all shots were fired by the snipers or the assault team.

PNP and the National Bureau of Investigation (NBI) agents went to Hong Kong Monday to get the sworn testimonies of some of the survivors of the Aug. 23 hostage crisis. They will also be seeking help of Hong Kong authorities who have more advanced technology. The agents will return to Manila on Friday.

De Lima said IIRC members will have an "internal session" with the PNP and NBI agents next Monday to review the results of the ballistics exam and the statements made by the hostage survivors.