According to police reports, Lockley told police he and Paschall went to the parking lot to rob someone.
When the two suspects arrived, they first walked past the victim, who was standing by his car, police reports said. They approached him as he walked toward the building, police reports said.
Lockley told police he pulled out a gun, put it to Hovis' head and told him to freeze, police reports said. Lockley then told police he cocked the gun.
Hovis raised his hands and was allegedly told it was a robbery and that he was to hand over his money. Some money was taken along with some papers and a watch, police reports said.
Lockley told police he tried to uncock the gun and when he did, it went off, striking Hovis in the head, police reports said.
Paschall, who pleaded guilty Aug. 12 to a third-degree burglary charge, had been allowed to remain free on bond pending completion of a pre-sentence investigation ordered by Washington County Circuit Judge Frederick C. Wright III.
Lockley was arrested at Hagerstown City Police headquarters at 7:08 p.m. Tuesday shortly after an interview with Detectives Mark Renner and Wayne Shank.
Lockley led investigators to Paschall, who was arrested at 11:08 p.m., police said. He was picked up in a vehicle in the first block of East Baltimore Street, police said.
Investigators would not say Wednesday how they developed the men as suspects.
"This case has got to go to trial. If we go discussing details, that can come back to hurt us," said Sgt. Rick Johnson, lead investigator in the case.
Detectives were busy Wednesday gathering additional evidence and double-checking facts, Johnson said.
"Just because an arrest is made doesn't mean the investigation is over," he said.
Paschall's burglary charge stemmed from the March 25 burglary of a home at 17836 College Road, court records said. Originally charged with burglary, felony theft and destruction of property, he could face up to 10 years in prison for a third-degree felony burglary conviction.
More than $1,000 worth of clothing, video games and pagers were taken from the home, including nearly $500 in cash.
All but the cash was recovered at a home on Hayes Avenue, according to Trooper First Class Mike Potter of the Maryland State Police.
A neighbor spotted a car driving away from the home and called police. The description of the car was familiar to the burglary victims, and that led to Paschall's arrest, Potter said.
Police began searching for clues to Hovis' murder after officers were called to the rear of 23 E. Washington St. early Monday morning. A witness told police Monday she heard a "pop" and saw two men running from the area just before Hovis was found in the parking lot in downtown Hagerstown.
The Adult Book Store, which is located at 23 E. Washington St., was still open at the time Hovis was found, Johnson said.
His vehicle, a white 1990 Chevrolet Geo with a pink stripe on the side, was found in the area where the body was found, Johnson said.
Staff Writer Brendan Kirby contributed to this story.