A German, Swiss and British man have been found stabbed to death in a house on the Philippine tourist island of Boracay.
A friend of the German owner of the house found the bodies of the three men and a Filipino maid on Monday, police said.
The foreign victims were identified as the owner (69) of the house, a Swiss guest and a Briton (59) who had recently arrived in Boracay.
"Our investigators are looking into robbery as the possible motive for the killings," police said. The two-storey house had been ransacked, with drawers and cabinets open and beds overturned, he said.
Police were questioning 25 construction workers as possible suspects after two blood-stained knives were found in the kitchen.
The workers, who were landscaping and working on a swimming pool, were the only people allowed in the property, which sits on top of a small hill.
"It's an isolated place and this could be an inside job," he said. "The suspects even tried to wash away the evidence but our investigators found blood stains," a police officer said.