Manuel Tolentino, Lagro barangay chairman, said they expect Cadiao, who was last seen running away from the house minutes before the fire, to turn up soon.
"We believe he will come out to shed light on the incident," Tolentino told The STAR.
The barangay chairman said he has formed a special night tracking team composed of barangay tanods who will monitor the outskirts of the barangay and the vicinity of the fire scene.
"We believe he is just in the vicinity and we want to assure him that we will provide him with all the necessary assistance once he comes out and cooperates with investigators," Tolentino said.
He also said the search for the 32-year-old son of Raymond and Charito Cadiao was expanded to the nearby La Mesa Dam area.
Cadiao, a seasoned mountain climber, was last seen fleeing half naked toward the forested area of the dam minutes after the fire broke out and trapped his parents and daughters.
According to relatives, Cadiao went through a traumatic experience several years ago when armed men believed to be communist rebels held him captive during a mountain climbing expedition.
He was tortured on suspicion that he was as a military informer, relatives said. After several weeks in captivity, Cadiao managed to escape from his captors and was reunited with his family.
But since his return, he has been exhibiting abnormal behavior, refusing to see people, including his friends.
A barangay resident, who requested anonymity, said Cadiao sometimes becomes violent, forcing his family to keep him confined to their home.
Chief Inspector Oscar Villegas, Quezon City fire chief, said they will issue an initial report on the fire as soon as the autopsy report and lab analysis are released by the Scene of the Crime Operatives of the Philippine National Police (PNP).