From GMA News:
According to police reports, Ampatuan and about 100 gunmen clad in camouflage fatigues robbed the victims - 21 females and 36 males - that rode on a convoy heading toward Shariff Aguak town.
Most if not all of the women’s pants were unzipped, but this wasn’t the case among the males victimized in the massacre, observes police Chief. Supt. Felicisimo Khu Jr., the head of a group of authorities that investigated the November 23 crime scene in Ampatuan, Maguindanao.
“It therefore gives you the impression that the women were raped," says Khu, deputy director general for administration of the Philippine National Police in Region 12.
But vaginal smear tests conducted by the National Bureau of Investigation yielded negative results. Not one of the 15 women examined had traces of human sperm, Floresto Arizala, chief of the NBI’s Medico-Legal Division said on Monday.
Bloating could be the cause, according to Arizala. “Bloating and decomposition will actually force (down) the zipper…Yung huli kong nakita 23 lang waistline na reported, nang mare-examine almost 40," Arizala says.
However, Khu’s observation differs from that of Arizala. The police officer said that the authorities who first went to the crime scene - about three hours after the grisly killings took place - saw that the pants of the women were already unzipped.
If it takes eight to nine hours before a dead body bloats as pointed out by Molino, it indicates that the pants had already been unzipped even before the bodies got bloated.