The suspect, lawyer Benito Salazar, 47, surrendered to New Washington Mayor Eduardo Peralta and Superintendent Jimmy Rivera, Aklan police director, after allegedly fatally shooting Munding Rodriguez, 43.
Police, however, said the incident was not politically motivated, and that personal grudge was the likely motive.
Reports said Rodriguez headed the porters group of Eagle Port Authority, of which Salazar is the operations chief.
Rodriguez was a staunch supporter of congressional candidate Mationg Leovigildo. Salazar was reportedly one of Lacsons lawyers in the celebrated Kuratong Baleleng rubout case.
Senior Superintendent Rodolfo Ibardo, chief of staff of the Region 6 police, said Salazar allegedly shot Rodriguez with a caliber .45 pistol, based on empty shells found at the crime scene.
Reports said the victim was gunned down while being interviewed by Jodel Rentillo of Bombo Radyo.
Salazar is now detained at Camp Batillano in Kalibo, Aklans capital town.