A man granted a new trial on charges he started a blaze that killed three firefighters has been released from prison after 20 years behind bars.

Gregory Brown Jr., 39, walked out of the Allegheny County Jail on Friday evening, free from state custody for the first time since 1996, when he was charged in the fire at his mother's East Hills home.

"I'm innocent. I'm happy to be out," said Brown, who was greeted by his attorneys and several relatives.

He embraced his mother, Darlene Buckner, and they walked out with their arms around each other.

"This is the moment I've been waiting for, for a long time. And I'm very happy for this day," she said.

Prosecutors had alleged that Brown, then 17, poured a half-gallon of gasoline on some clothes in the basement of the four-story home and started the blaze in 1995 in hopes of collecting $20,000 in insurance money for a down payment on a new home.

Pittsburgh fire Capt. Thomas Brooks, 42, and firefighters Marc Kolenda, 27, and Patricia Conroy, 43, suffocated when their air tanks ran out as they tried to escape from the rapidly burning home, authorities said.

Brown was convicted of murder, arson and insurance fraud and sentenced to three life terms. His mother was convicted of insurance fraud and was placed on probation.

Brown's conviction was thrown out after the defense said prosecutors and a federal agent failed to turn over evidence that witnesses were offered money in exchange for their testimonies.

Brown was scheduled to go on trial again in January, but prosecutors turned over jurisdiction to the federal courts. Federal prosecutors obtained an indictment on a charge of malicious destruction of property by fire resulting in death, which carries a maximum penalty of life in prison.

Brown expressed gratitude to his legal team for his release, repeating that he was innocent "like hundreds of others in here in my position."

"I just got lucky," he said. "I got the right legal team behind me. Others don't. So, you know, it's bittersweet."

Defense attorney David Fawcett, who has condemned the move of the case to federal court, stopped his client from speaking, citing the pending trial, after Brown told reporters: "There wasn't even a crime committed. It wasn't even an arson."

"It was a tragedy and we pray for the families of the firefighters. But as we've said from Day One, one tragedy should not beget another," Fawcett said.

He said he had advised his client to enjoy his time with his relatives.

"God bless him and the time he's going to have with his family."