QUEZON CITY - Former senator Rene Saguisag, who was once a law professor in San Beda College, on Tuesday said he regrets a law school not expelling President Rodrigo Duterte after he shot another student in 1972.

Duterte gave a vague account of the gun-related incident as he delivered a speech in Iloilo during the 2016 presidential campaign.

Duterte said he shot a schoolmate who allegedly bullied him for being a Visayan, but added that the victim did not die from his gunshot wound.

"Kinakantiyawan siya ni Octavio Goco na probinsyano so inabangan, binaril. Noon pa lang nun, talagang medyo trigger-happy na," Saguisag who "virtually ran the law school" then told ABS-CBN News.

"Sabi yata ng mga fraternity brothers niya, 'Digong, sabihin mo aksidente.' Ang kwento sa akin ng reliable source, sabi niya, 'Hindi, talagang gusto kong barilin,'" Saiguisag said.

The former lawmaker said he "voted to expel" Duterte over the incident, but was "outvoted by the priest and the dean" who gave due consideration because Duterte was a graduating student.

Saguisag said Duterte was able to earn his law degree from San Beda in 1972, but was not allowed to attend the graduation ceremonies.

"Siguro if he was disciplined in 1972, he would not be what he is today kasi ang tingin niya siguro he could get away with anything."

Despite the Duterte administration's "false starts," Saguisag said he is still hopeful that the tough-talking chief executive will have a change of heart and a shift in policies.

"I cannot underrate anybody's capacity for subjective change or growth but I hope he will review the past few months and change course," Saguisag said.

"I remain hopeful that he will still change because his failure is your failure, my failure. His success will be everyone's," he added.