Senior Superintendent Norlito Bautista told The STAR that 15 of the stab wounds inflicted on 58-year-old Arthur Juada were fatal, while the rest were "defense wounds."
The police have identified Juadas attackers, but Bautista refused to name them pending their arrest.
Bautista said Juada knew his attackers because there were no signs of forced entry in his room at the Punta Villa Resort in Arevalo district.
The police said two men and a woman entered Juadas room, bringing with them what looked liked a bag for a laptop computer.
Bautista said a roomboy of the Punta Villa Resort discovered the bloodied and naked body of Juada when he checked on him because his fellow participants in a seminar there had already checked out.
Juadas brother Adolfo said in a radio interview that there were signs of struggle inside the room, with blood splattered on the walls and curtains.
"We have not yet established the motive, but what we know is that the victim knew the perpetrators because there was no forced entry," Bautista said.
The police, however, were looking at the robbery angle because Juadas cellular phone, wallet, wristwatch and other valuables were missing.