Lawmakers are seeking clarification on the basis of the early release of US Marine Lance Corporal Joseph Scott Pemberton thru the Good Conduct Time Allowance (GCTA).

Senate President Vicente Sotto III and Sen. Panfilo Lacson said Thursday they would have to look into the computation of authorities on Pemberton's sentence, which was reduced on account of good behavior.

Pemberton was convicted for homicide for killing Filipino transwoman Jennifer Laude in Olongapo City on October 2014. He was sentenced six to 12 years in prison for his crime, but in 2016, his sentence was reduced to 10 years.

Last Sept. 1, the Olongapo City Regional Court Branch 74 granted his plea for early release, ruling that the American has already served his sentence under the GCTA law.

"Siyempre dahil Filipino ang biktima at foreigner ang na-convict, masama ang loob natin (Of course because the victim is a Filipino and a foreign was convicted for it, we are offended by this)," Lacson said in an interview with radio DZAR.

He, however, noted there might be considerations that have not been discussed publicly for the court to decide to set Pemberton free.

Sotto said this could be included in the Senate's investigation of the controversies hounding the Bureau of Correction's (BuCor) application of the GCTA rule.

"It is a good thing that the Blue Ribbon Committee of the Senate has not ended the hearing on the GCTA," Sotto told CNN Philippines in an interview.

Sotto noted that the Senate panel had only suspended its legislative inquiry on the issue last year, and that Sen. Richard Gordon, its chairman, has yet to come up with the committee report.

"I am sure we can take it up. That will be a good resort to be able to find out if (the computation) is correct," he said.

He said the Senate, however, cannot intervene with Pemberton's release "because we have separation of powers with the Judiciary."