Metro Manila (CNN Philippines, August 22) — President Rodrigo Duterte won't allow convicted rapist and murderer Antonio Sanchez to be released early from prison because he is not qualified to benefit from the law that shortens the jail sentence of inmates based on good behavior, Presidential Spokesperson Sal Panelo said on Friday.

"Mr. Sanchez, under Republic Act 10592, is not eligible, so the President as the chief enforcer of the law will have to follow the law," he said.

He said the Palace recently reviewed the the law on Good Conduct Time Allowance (GCTA) after the public outcry on the former Calauan, Laguna mayor's possible early release. He said the good conduct-based sentence reduction policy categorically excluded persons charged with heinous crimes and recidivists from the benefit of its coverage.

"This is the letter and the spirit of the law. Thus, the inevitable conclusion is that all those convicted of a heinous crime, including Mr. Antonio Sanchez, would be ineligible and disqualified from availing the benefits of the GCTA," he said.

Panelo, who was one of the lawyers of Sanchez in the 1993 highly-publicized trial of the rape-slay of University of the Philippines-Los Baños students Mary Eileen Sarmenta and Allan Gomez, said Duterte will be furious if the ex-mayor walks free soon.

"Magagalit siya because if the law says he’s disqualified, bakit mo icoconsider?" he said.

Sanchez, along with other six individuals, was convicted in 1995 for the rape and murder case. They were sentenced to seven terms of reclusion perpetua or up to 40 years of imprisonment. This would total to 280 years, but under the Revised Penal Code, maximum prison time shall not exceed 40 years.

READ: The heinous crimes of ex-Mayor Antonio Sanchez

Justice Secretary Menardo Guevarra earlier said the mayor was among the 11,000 inmates and detainees who will benefit from a 2013 law increasing GCTA. The policy, enacted by then President Benigno “Noynoy” Aquino III, was designed to be applied prospectively, which means it would only cover those convicted by the time it was passed into law. A Supreme Court ruling, however, approved a petition which sought the retroactive implementation of the measure.

Bureau of Corrections chief Nicanor Faeldon also said it is "impossible" for Sanchez to to walk free soon, even if he qualified for the good conduct-based sentence reduction policy.

READ: Early release ‘impossible’ for Antonio Sanchez – BuCor chief

He said the recomputation of Sanchez’s time allowance based on his supposed good conduct behind bars would only begin in 2015, the year when he last committed a violation inside the New Bilibid Prison. He was caught smuggling illegal drugs and contraband in his jail cell in 2006, 2010, and 2015.

Faeldon said Sanchez’s records in prison may be reviewed next month. He urged the public to witness the evaluation.