John Iris Daan, 19, a resident of the place, was arrested Sunday night after being tagged by witnesses as one of the two men behind the slaying of Castro, a traffic policeman.
Villacin confirmed that robbery was the motive behind the killing, saying that they would use Castro's two companions during the incident as witnesses against the suspects.
Last Monday night, San Roque barangay officials recovered Castro's driver's license, pay slips, Armed Forces of the Philippines Savings and Loan Association Inc. card, Philippine Health Insurance Corp. card, residence certificate and among other his personal documents at a mangrove swamp near the crime scene.
Villacin said that before they left, the suspects had reportedly ransacked Castro's car.
Villacin revealed that Daan's group would wait at a makeshift hut in the area to make plans and monitor their victims.
Daan, however, denied the allegations, saying that a certain Ismael Secretaria alias "Jun Jun Kimpang" was the one who shot Castro dead.
Daan revealed that Secretaria was a former police asset who tagged him as the one who shot Castro during police questioning last Saturday. Secretaria reportedly fled after the questioning.
Daan said he is ready to testify that Secretaria was the one who shot Castro because he witnessed the incident but did not immediately report it to police for fear that he might be Secretaria's next target. - Norvie S. Misa