"The family offered P100,000 for anybody who could provide information that would lead to the possible identification of the perpetrators," Western Visayas police director Chief Superintendent George Aliño said.
Aliño revealed yesterday the family of German property developer and villa owner Anton Faustenhauser informed him of the bounty.
But the family, he said, imposed several conditions, all directed at the credibility of the information which will be used to convict the killers.
Aliño could not say if the reward was put up collectively by the families of the three foreign victims.
Aside from Faustenhauser, the slain foreigners were identified as Swiss-born art gallery owner Manfred Schoeni and Hong Kong-based British architect John Cowperthwaite.
A Filipina maid identified as Erma Sarmiento was also among those killed in what the police said was a case of bungled robbery.
The victims were found brutally stabbed to death early Sunday in the three-story luxury villa owned by Faustenhauser.
Aliño said they have recovered additional evidence from the crime scene.
"We found a clutch bag the size of a knapsack, bloodstained, and inside are Schoeni’s passport, credit card and ticket (but) no cash (was) recovered in the bag," he said.
Aliño said this bolstered theories that the motive of the killing was robbery since the bag was recovered outside the house.
He said investigators are also lifting several prints from the crime scene.
"Once we are able to complete the investigation, gather all the evidence and the testimonies that we need, we will file the case," he said.
Aliño said they are not ruling out other possibilities as investigators are still trying to gather information from the nine remaining suspects.
Initially 25 construction workers were questioned after the bodies were found on Sunday morning.
Most of the suspects are workers hired by Faustenhauser for the construction of his swimming pool and the landscaping of his garden.
"On the other angles, as we go on with our investigation and solid evidence or other testimonies would point to other persons then we will start to investigate this," Aliño said.
Aliño earlier briefed President Arroyo on the progress of the investigation as she personally visited the crime scene last Thursday.
Mrs. Arroyo said she is convinced the murder of the three foreigners and their Filipina maid was an isolated incident which should not discourage local and foreign tourists.
She said the incident took place in a "very secluded" private property outside the tourist-frequented areas on the island.
Following instructions from the President, Aliño had a meeting with Boracay resort owners, police and provincial officials of Aklan to implement additional security measures.
Aliño said the agreement is to deploy additional bike patrols and roving policemen on the island.
Aliño also urged owners of private resorts, villas and residents in Boracay to employ the services of security guards, particularly if their locations are far from the tourist-frequented areas.
Stakeholders in Boracay also announced their plan to implement an ID system among all the construction workers and all employees of establishments on the island.
There will be a uniform ID but different color scheme based on the nature of their work, they said.
Despite the weekend murders, Aliño said the island still managed to attract foreign and local visitors.
"The incident happened in a very remote and isolated area.. (This) is a case of robbery and it happened in private area that only few people can go to," Aliño said.