MANILA, Philippines -- The colonel found dead in his Fort Bonifacio quarters Thursday was the third soldier who took part in a fierce 2000 battle against Abu Sayyaf extremists in Basilan to die in an alleged suicide, his fellow Scout Rangers said.

Aside from Colonel Roberto Caldeo, a sergeant and a lieutenant of the elite unit allegedly also took their own lives years after the three-day assault on Puno (Mt.) Mohaji in Isabela City in late April 2000, according to a Scout Ranger junior officer who was part of the operation.

Caldeo commanded the 1st Scout Ranger Battalion, which was tasked to assault Puno Mohaji to rescue dozens of teachers, students, and a Catholic priest held hostage by the Abu Sayyaf.

Another junior officer in the Rangers who was stationed in Basilan at the time, said the three soldiers could have been driven to suicide because of depression over the assault, in which six soldiers were killed and 50 wounded. More than 20 Abu Sayyaf fighters were also killed.

"Wala talagang stress management sa Army [There really is no stress management in the Army]," the second source said.

The junior officers spoke on condition of anonymity because they are not authorized to speak to media.

Caldeo was found dead with a gunshot wound to his forehead on Thursday morning.

Army spokesman Lieutenant Colonel Ernesto Torres Jr. said a note and a handgun found on the scene could indicate suicide, although he stressed that the police investigation into the incident is continuing.

A classmate of Caldeo’s at the Philippine Military Academy (PMA) confirmed his late “mistah” was bothered by the Puno Mohaji incident up until the time of his death.

"I believe so, that [Puno Mohaji] is one of the things he shared with us. A number of soldiers died under his watch," Colonel Daniel Lucero, president of PMA Class 1983 to which Caldeo belonged, said.

Asked if Caldeo may have felt guilty because of the casualties, Lucero said: "Not actually guilt. It's care for the affected families [of the casualties]."

"Leading men to battle could mean losing lives," said Lucero, a former military spokesman who is the current head executive assistant to the Armed Forces Chief of Staff.

Another classmate, Colonel Ricardo Visaya, said Caldeo was "very secretive" especially when it came to personal problems.

Torres said the Army does have a team of medical experts who conduct stress management but conceded that: "We can't say that 100 percent [of troops] undergo the procedure."

He explained that those who figure in major encounters are prioritized for stress debriefing but could not immediately confirm if the soldiers involved in the Puno Mohaji operation underwent this.

Torres said ground commanders are expected to be "creative" and conduct stress management on their men. Troops who have not gone home for some time or those with family problems are allowed to go on vacation.

"We have professional medical experts [but] hindi natin laging kasama sila [they are not always with us]," he said.

The first Ranger officer joked that soldiers go to watering holes for stress debriefing.

The Puno Mohaji raid earned for Caldeo the Distinguished Conduct Star, the second highest combat medal in the military, but the honor came three years after the encounter.

It also earned for a young officer, then Second Lieutenant Herbert Dilag, the military's highest honor, the Medal of Valor. Dilag led a 14-man team on a "suicide mission" that finally overran the bandit camp.

But Caldeo was relieved as brigade commander after the hostages were rescued from Puno Mohaji and was reassigned to the 33rd Infantry Battalion in Sulu province.

The first source claimed Caldeo earned the ire of superiors, one of whom threatened to remove the “tabak” or native sword on the Scout Ranger emblem, as his troops suffered casualties during the Puno Mohaji assault.

"Instead of [getting] praise, we got criticized," he said.