The former New York City police officer whose conviction for a 1997 murder was overturned Friday walked out of prison, accompanied by his mother and friends.

Richard D. DiGuglielmo left the premises of the Eastern Correctional Facility in Ulster County, where he has served 11 years, shortly after 2:50 p.m., when his sentence officially ended.

?He's pretty overwhelmed,? says Stephen Lewis, DiGuglielemo?s attorney. ?He wasn't even aware of this until this morning when a corrections officer asked him when he was going home.?

DiGuglielmo's release came 24 hours after Westchester County Court Judge Rory Bellantoni vacated his 20-years-to-life sentence for the shooting death of Charles Campbell outside the DiGuglielmo family deli in Dobbs Ferry in 1996.

Following a hearing in 2007, Bellantoni determined there were flaws in the prosecution of the officer?s case.

A witness originally told police DiGuglielmo was justified in shooting Campbell because he did so in self defense. The witness claimed Campbell was about to hit DiGuglielmo?s father with a baseball bat before he was shot. Later, the witness testified Campbell was only holding the bat at the time he was shot. He has since said police pressed him to change his story.

Westchester County District Attorney Janet DiFiore did not prevent DiGuglielmo's release from prison, but she plans to appeal the overturning of the conviction.

?Richard DiGuglielmo, 11 years after he was convicted, is going home with his family, and we'll worry about any and all appeals,? Lewis says. ?Everybody has always believed that he shouldn't be here.?

For interviews about Judge Bellantoni's decision to drop DiGuglielmo's conviction, go to your digital cable box and select iO Extra, Channel 612.

AP wire reports contribute to this article.

Click here for reactions from Charles Campbell's family