The suspect in the killings of two Australians and their Filipina companion at a hotel in a popular resort city south of Manila was a former pool cleaner who allegedly wanted to retaliate against the hotel for firing him.

The suspect claimed that he randomly barged into the victims’ room last week because its window was open, Philippine officials said on Wednesday.

A hotel worker found the bodies of three victims, whose hands and feet were tied, on 10 July in a room at a hotel in the popular resort of Tagaytay city, south of Manila.

The victims were Sydney man David James Fisk, 57, his partner, Lucita Barquin Cortez, 55, a Philippine-born Australian citizen, and a younger relative of Cortez’s Filipina daughter-in-law.

In a pre-dawn news conference at the city hall, Tagaytay mayor Abraham Tolentino and police officials presented the handcuffed suspect, who was wearing a hoodie, dark eyeglasses and a face mask. The man, whose identity was not released, will face criminal complaints for the killings and robbery, Tagaytay police chief Charles Daven Capagcuan said.

The mayor repeated an apology to the victims’ families and to Australia for the killings.

“We are pleased to present to you the main suspect in this brutal crime and as promised that within a week, we will resolve and give justice,” Tolentino said.

Capagcuan told reporters ahead of the news conference that the breakthrough in the case came when the suspect was allegedly identified by at least three hotel employees based on his image, which was captured by security cameras showing a part of his face when his mask slid down.

The identification and information from witnesses eventually led authorities to the suspect’s Batangas home province near Tagaytay, where he decided to surrender on Tuesday, the police chief said.

“He wanted to get back at the hotel management for his dismissal,” Capagcuan claimed, adding that the suspect used to work as a swimming pool cleaner but was allegedly fired by the hotel in March after he was linked to a robbery in one of the rooms.

Police officials planned to file criminal complaints of robbery in addition to the killings against the suspect.

The man allegedly took the watch and shoes of the Australian male victim after attacking him with a knife and suffocating his partner and her daughter-in-law, Capagcuan said.

“He barged randomly with a knife into the room because its window was open,” Capagcuan said.

The Australian woman and her daughter-in-law are to be buried in their family’s home province in the Philippines while the remains of the Australian man would be flown to Sydney on Tuesday, Tolentino said.

The Australian couple had planned to fly back to Australia on 10 July, the day they were killed, but decided to briefly take a vacation in Tagaytay, the Filipino son of the slain Australian-Filipino woman said.

Tagaytay, about 60km south of Manila, is popular among local and foreign tourists who flock there for its cool weather and to view one of the world’s smallest active volcanos in a lake from elevated ridges teeming with restaurants, viewing decks and hotels, including the one where last week’s killings took place.