Esperat, a hard-hitting columnist of Midland Review, a weekly newspaper in Tacurong City, was shot dead by a suspected hired killer inside her house on Maundy Thursday.
The police still have no solid clues on the identity of the gunman and the exact motive for the attack.
Mangudadatu said he will immediately pay P200,000 to any informant who can provide on the whereabouts of the gunman.
"This amount is just an initial offer. I will be flexible in increasing it if the informant can identity the real brains in the murder of Marlene Esperat," Mangudadatu said. — John Unson a