Prime suspect Christian Espat remains detained along with a number of other men - as many as 12 we are told.

Espat - who police have described as a notorious gang figure who Graniel had a misunderstanding with - has said he was in Benque Viejo when the murder occurred on Sunday morning.

It happened at around 10:00 one mile west of San Pedro Town within the town lagoon. That's where Graniel and Swank were fly fishing when a dark color skiff passed by and opened fire on them.

Graniel was found dead behind the wheel of the vessel while Swank was 30 feet away, face down in the water, most likely where he had been fly fishing. Both men had been shot to the chest and the face.