MANILA, Philippines?Several high-powered firearms seized in a series of raids in Maguindanao province over the past weeks were police-issued firearms, Philippine National Police Director General Jesus Verzosa said on Monday.

In an interview, Verzosa said that of the more than 800 firearms seized throughout the province of Maguindanao during and after the declaration of martial law there, more than 20 were PNP-issued.

He said most of those that were PNP-issued were M16 rifles.

?There was an unauthorized selling [of firearms] and this is subject to investigation. We are now accounting the firearms and ammunition that were seized in Maguindanao. There could have been an illegal purchase and this is what we?re considering now. The illegal transfer or illegal selling may not have necessarily come from the inventory of the PNP but also from other sources or dealers,? Verzosa said.

He added that the PNP?s Logistics Service is in the process of conducting an inventory of all the other firearms seized during a series of raids in the province.

Verzosa admitted having difficulty in the inventory of firearms, citing ?problems? in the records of firearms there.

He said that the leadership of the PNP will be investigating all past and present police logistics officers assigned in Maguindanao because of the incident.

?Nagkaroon ng problema sa records dun sa ARMM so again iniimbestigahan natin yung mga dating logistics officers dun at nung nagkaruon ng gulo dun,? Verzosa said.

The most recent raid in the ARMM capitol compound led to another arms cache, including several M16 rifles, a 50-caliber machine gun, M60 machine gun, and a K3 submachine gun or ?minimi.?

Verzosa said the PNP is prioritizing the ballistics examination on the seized K3 submachine gun, after witnesses claimed that Datu Unsay Mayor Andal Ampatuan Jr. allegedly used a K3 submachine gun to kill several of the victims in the massacre of at least 57 people last November 23.