Officials say a man who set fire to a Seattle warehouse, killing four firefighters in 1995, is scheduled to be released from prison Thursday.

Martin Pang will leave the penitentiary in Walla Walla after serving about 20 years in his 35-year sentence.

Pang was convicted of four counts of manslaughter after setting a fire in his parents’ Chinatown International District warehouse in 1995.

Firefighters Walter Kilgore, Gregory Shoemaker, Randall Terlicker and James Brown died when the floor inside the frozen-food warehouse collapsed.