Reyes said charges of illegal possession of firearms would be filed against Dionisio Bernos after investigators recovered an M-16 rifle and caliber .45 pistol inside his rural bank.
"This is, indeed, a major breakthrough in our investigation, and hopefully will lead us to the real masterminds," he said.
Reyes, concurrent chief of the National Anti-Crime Task Force (NACTAF), instructed investigators not to leave the area "until we have solved the case."
Bernos, 31, was shot dead while watching a basketball game at the Sangguniang Kabataan Park in La Paz last Jan. 13.
Reyes said the filing of the charges against Bernos’ uncle is based on the recommendation of Chief Superintendent Pedro Tango, acting chief of the Criminal Investigation and Detection Group (CIDG).
Reyes said scene-of-the-crime operatives are now conducting ballistic tests on the recovered firearms to determine if the bullets that killed Bernos were fired from them.
If the tests yield positive results, police said they would have concrete basis to file murder charges against Bernos’ uncle.
Reyes went to Abra last Sunday to personally oversee the progress of the investigation.
During his visit, he ordered the local police to beef up security in the province to curb criminality.
Earlier, Reyes said Bernos’ murder could signal the start of fresh hostilities among warring Abra politicians.
He gave assurances, though, that the police would see to it that there would be no more bloodshed in the northern province.
Bernos’ family earlier expressed suspicion that the mayor’s killing might be politically motivated.
Reyes has sworn in Bernos’ brother, Joseph, 27, the vice mayor, as the new mayor of La Paz town.