The statement dated July 11 and signed by Victor Rivero, who claimed to be an NPA spokesman, was sent to Bombo Radyo Dagupan via postal service. It was postmarked July 15 in Dagupan City and was received by the radio station two days later.
Superintendent Rayland Malenab, intelligence chief of the provincial police, said they will carefully study the content of the letter and the litany of "sins" which the NPA alleged Vice Mayor Adolfo Aquino had committed.
Aquino and his driver, Victor Villanueva, were laid to rest last Saturday, with an estimated 3,000 people joining the funeral.
In the statement, written entirely in Filipino, the NPAs Lucio de Guzman Command, which is part of the Southern Tagalog regional committee, said it was responsible for the gunslaying.
The NPA command accused Aquino of having committed crimes and inhuman acts against the poor people and laborers of Mindoro, including his non-payment for services rendered during a treasure hunt.
It also mentioned that it knew something about Aquinos alleged involvement in a multimillion-peso "textbook scam" at the then Department of Education, Culture and Sports.
Marvin Modelo, station manager of Bombo Radyo Dagupan, told The STAR that Adolfos widow, Eden, admitted to one of his reporters that they just had a little share in the treasure hunt.
Mapandan Mayor Jose Ferdinand Calimlim earlier cried foul over speculations that politics was behind Aquinos killing. The two were former political allies.
Calimlim said he would rather keep silent about the NPA statement and let the police do their job.
Meanwhile, the members of the entire Mapandan police force, who were relieved by Philippine National Police chief Director General Arturo Lomibao following the killing, are still undergoing retraining under the Provincial Mobile Group in Alaminos City.