"We are looking in that direction," said Superintendent Remus Canieso, head of the island’s special police unit. He would not elaborate.
Canieso said investigators were looking at all angles of the killing earlier this month that rocked the normally quiet resort island.
Boracay has about 12,400 local residents, many of them Westerners who part-own some of the 124 major hotels, bars and restaurants.
Bordering the provinces of Mindoro to the northwest and Romblon to the north, Boracay has been considered relatively safe for tourists as it is some distance from the Muslim and communist rebellions further south.
Swiss-born art gallery owner Manfred Schoeni, German property developer and villa owner Anton Faustenhauser, and Hong Kong-based British architect John Cowperthwaite and a Filipina maid were found stabbed to death last May 2 in Faustenhauser’s luxurious villa La Dolce Vita.
Police initially questioned 25 Filipino construction workers on the site next door and were looking into the possibility that the murders were the result of a bungled robbery.
Canieso said all of the construction workers had since been released after questioning but on the condition "that they be available for further questioning if needed."
Robbery is still the most likely motive for the killing, Canieso said but he would await the findings of a technical commission before naming any suspects.
The killing of the three foreigners and the Filipina in the resort, famed for its white sands and idyllic lifestyle, shocked the nation and raised fears that the tourism industry could be affected.
President Arroyo and other officials have repeatedly stressed that the crime was an isolated incident and that Boracay, which is visited by thousands of foreign tourists each year, has largely been crime-free.
Schoeni was a leading dealer in Chinese contemporary art with two galleries in Hong Kong’s fashionable SoHo district. The British architect was the son of Sir John Cowperthwaite, Hong Kong’s financial secretary between 1961 and 1971.
Faustenhauser, 69, had finished building his house about 14 months ago and was subdividing his one-hectare site into building plots. Schoeni was building a villa next door. — AFP