A change of heart and story by a key witness in the 1997 murder trial of a former New York City police officer could lead a judge to overturn the conviction.

Richard DiGuglielmo was convicted of murder for fatally shooting Charles Campbell outside the DiGuglielmo family's Dobbs Ferry deli. Campbell had parked in front of the deli on Oct. 3, 1996, and was confronted by DiGuglielmo's father. Police said the pair fought, Campbell took out a baseball bat and DiGuglielmo went inside to get a gun.

Michael Dillon, one of a dozen witnesses, testified Campbell was backing away when he was shot. However, on the night in question, Dillon told WNBC he thought the shooting was an act of self-defense. Defense attorneys and Dillon now claim he felt pressured by police to change his story.

On Wednesday, a judge agreed there is enough evidence to proceed with a hearing on Monday, which could lead to an overturning of the conviction.