The accounts of two people who said they watched an accused killer shoot a Washington man dead with a shotgun led to the suspect’s arrest after two decades, according to court documents.

The May 26, 1992, incident that led to the death of Chet Hunter Matthews, 27, was originally planned as a robbery, two witnesses told police, according to documents.

Several men, including the witnesses, met in Arlington and drive to nearby East Potomac Park in Washington, where they found a car with Matthews and a woman inside, court documents said.

Lamont Deshawn Terry, now 37, had a shotgun, the witnesses told police. According to court documents, Terry ordered Matthews out of the car while the other men made the woman lie on the ground and searched the car for valuables.

Terry demanded property from Matthews, who pleaded not to be shot from his knees, according to court documents. Terry shot him in the chest, then threw the gun into a nearby waterway, court documents said; the men then drove off.

The two witnesses — who police said identified Terry in a photo lineup — have pleaded guilty to their role in the robbery and homicide, court documents said. They are cooperating with authorities, and further details were not available.

Terry, of Columbia, S.C., arrested in January and charged with felony murder in the District on Monday.

Read more: The Post’s crime coverage