Valery Fabrikant, who shot four people dead at Concordia University in 1992, died in a Quebec prison on Saturday.

Correctional Service Canada put out a news release on Sunday stating he had died of apparent natural causes at the age of 86.

Fabrikant had been serving a life sentence since June 8, 1993.

On Aug. 24, 1992, Fabrikant, a former professor of mechanical engineering at Concordia University in Montreal, opened fire in the university’s engineering department building, killing four professors and wounding a secretary.

Fabrikant was facing dismissal before he committed his crime and accused his colleagues of stealing his work.

He died at Archambault Institution, a medium- and minimum-security prison in Sainte-Anne-des-Plaines, Que., in the Laurentians.

In 2020, the Canadian Parole Board denied Fabrikant’s request for release, saying he would pose an undue risk to society. In its decision, the parole board noted that after Fabrikant still did not acknowledge that he had targeted innocent people after 28 years behind bars.