Chief Superintendent Antonio Billones, Central Mindanao police director, refused to identify father and son, but said the Criminal Investigation and Detection Group (CIDG), which heads Task Force Esperat, is investigating them.
Billones declined to give details of the investigation.
Marlene Garcia-Esperat, a hard-hitting columnist for the Midland Review, was shot in the head with a caliber .45 pistol inside her home in Tacurong City in front of her 10-year-old son.
Reports said the gunman, assisted by a lookout, fled on board a motorcycle.
Billones said the CIDG is also looking into the possible involvement of a Department of Agriculture (DA) official in Cotabato City and a Tacurong contractor in the killing. He refused to elaborate.
Carlos Conde, secretary general of the National Union of Journalists of the Philippines (NUJP), clarified yesterday that Esperat was the third Filipino journalist slain this year.
The two others were Arnulfo Villanueva, a community newspaper columnist in Naic, Cavite who was killed last Feb. 28, and Edgar Amoro, a freelance broadcaster who was gunned down near a school in Pagadian City last Feb. 2.
Amoro was a vital witness to the killing of Pagadian City journalist Edgar Damalerio.
Conde said the government’s "lack of sincerity" in the campaign against graft and corruption "has contributed to the killing of journalists."
He said Esperat served as a resident ombudsman of the DA and filed several corruption cases before she resigned in 2004.
Because of threats to her life owing to her exposés, Esperat sought police protection. But on the day she was killed, she had allowed her bodyguards to go home for their Lenten break. — With Benjie Villa