MANILA, Philippines ? Police are still looking for at least seven more firearms used in the mass killing of 57 people in Maguindanao province, after only one firearm tested positive in the ballistics examination to date, authorities said on Thursday.

Chief Superintendent Arturo Cacdac, Philippine National Police Crime Laboratory chide, said in a press conference that they are in the process of testing 21 more firearms, consisting of two M16 rifles, one shotgun, four M14 rifles and 14 Garand rifles obtained from various police and paramilitary forces in Maguindanao.

Only one tested positive in ballistics exams so far: the M16 rifle of militiaman Ismael Canapia, who is now under police custody in Manila.

Ballistic exam results revealed that of the 126 spent shells from M16 rifles recovered at the crime scene, 23 of these came from Canapia?s firearm.

Cacdac said that apart from the spent shells from the M16 rifle, also recovered in the crime scene were three spent shells from an M14 rifle, 32 pieces of link chain of still unknown origin, and a piece of metal fragment.

?We will try our best to complete the exam but I would like to report that we are still looking for [several firearms],? Cacdac added.

Meanwhile, autopsy reports revealed that of the 37 bodies the PNP Crime Laboratory conducted autopsies on, most bore bruises on the body that were obtained ?ante mortem? or before death.

These bruises, according to Chief Inspector Dean Cabrera, medico legal officer, were found on different parts of the victims? bodies.

Of the victims? autopsied, only one was shot at close range, who was identified as Cecille Lechonsito, who also bore strong indications of sexual abuse.

Lechonsito was shot on the mouth, Cabrera revealed.

Forensic experts also said they could not determine if the victims were shot in a firing squad manner as well as the trajectory of the bullets at this time.

Six vehicles, including the backhoe, are now in the possession of forensic experts for examination as well.