Father Giancarlo Bossi, an Italian priest, was kidnapped more than a month ago in his parish in the volatile southern Philippines.
Father Bossi was seized by armed men on his way to church
He was a quiet man who had lived in the Philippines for more than a decade, and had, colleagues say, a deep love and understanding of the local people.
The Philippine military has been searching for him since his disappearance, as has the Moro Islamic Liberation Front (MILF), a rebel group that has signed a truce with the government.
But on Tuesday, the two heavily armed groups met each other, with devastating consequences.
Fourteen marines were killed as they searched for the priest in a place called Tipo Tipo, on the small island of Basilan, near the island of Mindanao. Ten of them were beheaded.
At least four rebels were also killed, with some reports claiming as many as 20 rebels lost their lives.
The military insists that the marines were ambushed by the MILF, and claims that the group was joined by members of Abu Sayyaf, a small extremist rebel group allegedly linked to al-Qaeda.
The beheadings point to Abu Sayyaf's involvement, as this is something the group has been known for in the past.
But Mohagher Iqbal, a spokesman for the MILF, said that Abu Sayyaf rebels were not present during Wednesday's clash.
The marines were heavily outnumbered by rebels
"We have no links to Abu Sayyaf, this is simply not true," he said.
"The battle was a legitimate fight... We acted in self-defence. [The marines] were in a territory that belongs to us, a place where they should not have been.
"We have an agreement whereby they are supposed to tell us of mass troop movements. They did not do this."
While admitting that his men were responsible for the deaths of the marines, he denied that his group had beheaded them.
"It is against Islam and it is against the Geneva Convention. It is an atrocity, a violation. We do not mutilate the enemy," he said.
"We are investigating, but it may well be that the beheadings were carried out by civilians - there are many people who hate the military and have their own legitimate grievances."
The military have no doubt as to who decapitated the marines.
"It was the MILF or groups linked to them," said Major Eugene Batara from his base in southern Mindanao.
There has been an uneasy truce since 2003 between the MILF and the military - bringing a tentative end to a decades-long separatist struggle.
But in reality there are frequent skirmishes between the military and various rebel groups in the restive south, and the truce with the MILF is still shaky.
The government in Manila, it seems, is not overly concerned about how this latest incident will affect the peace process.
"These are the hazards of the trade as far as members of the security forces are concerned," executive-secretary Eduardo Ermita told a press conference in Manila.
"Still, we are saddened by the incident and we commiserate with the families of these soldiers," he said.
Conflict resolution experts in Manila say that the beheading of the soldiers is clearly a cause for concern, but it is not a deal-breaker.
"Although these sort of events are very bad and beheadings strike fear and disgust in peoples hearts, I think the peace process is proving to be very robust," said Willy Torres, a Manila-based conflict management expert on Mindanao for the Asia Foundation.
"I am confident it is not enough to de-rail the peace process. Lots of civil society groups and those involved really want this process to continue. There is a real will there."
Members of the MILF and the Philippine military already talk regularly, and have formed a body to implement the ceasefire, the Co-ordinating Committee on the Cessation of Hostilities (CCCH).
They also put together an ad-hoc committee last month to help find Father Bossi, but its remit has already expired.
"More talks are planned between the government and the MILF, it is just a question of when they will be held," Mr Torres says.