Federal prosecutors allege that a man on parole for a federal drug conviction participated in a brazen ambush slaying on the South Side in January after following the victim home from the Cook County criminal courthouse.

Marquez Robinson, 25, also known as “Little Smoke,” was charged in a criminal complaint unsealed Monday in U.S. District Court with being a felon in possession of a firearm, court records show.

Robinson had been in custody in Cook County Jail since his arrest last month on burglary charges, according to court records. He first appeared at the Dirksen U.S. Courthouse on Friday on an allegation that he’d violated his supervised release for the drug conviction.

Robinson’s court-appointed attorney was not immediately available for comment.

The new charge relates to the slaying of Eric Vaughn, 28, who was shot multiple times on the afternoon of Jan. 31, shortly after appearing for a status hearing at the Leighton Criminal Court Building at 26th and California, where he had a pending gun case, records show.

According to the complaint, Marquez and two other still-unidentified suspects were in a stolen Nissan Maxima that was seen circling the block around the courthouse on the morning of the shooting. Later, surveillance video captured the same Nissan driving through alleys near the scene of the shooting, the complaint alleges.

Vaughn was standing on the sidewalk shortly after 1:30 p.m. when the Nissan pulled up and at least two gunmen got out and opened fire with semi-automatic weapons, according to the complaint.

A witness captured the end of the shooting on cell phone video that showed one suspect firing several times at point-blank range as the victim was on the ground bleeding, the complaint alleges. Robinson, meanwhile, dressed in a gray hooded sweatshirt, a black face mask and gray sweatpants, was seen running around the front of the car and getting into the driver’s seat while tucking what appeared to be a gun under his arm, the complaint alleges.

Vaughn was dead at the scene. Detectives found 52 shell casings of three calibers around his body, and a few days later a neighbor reported finding about “18 additional bullet casings from the bushes” near where Vaughn’s body was found, the complaint says.

About 30 minutes after the shooting, a vehicle fire was reported in an empty lot in south suburban Dixmoor, about 10 miles from the site of the slaying, where the stolen Nissan was found “abandoned and burning,” the complaint alleges.

According to the complaint, law enforcement used the cell phone information Robinson had given to federal probation officials upon his release in the drug case to track his location on the day of the shooting.

License plate readers and surveillance cameras showed him departing a home on South Hale Avenue at about 8 a.m. that morning in a black Range Rover. That same vehicle was also seen along with the Nissan circling around the area on South Morgan Street for several hours before Vaughn was shot, the complaint alleges.

Location information also showed Robinson’s phone pinged from near the scene where the Nissan was found on fire, according to the complaint. At 2:30 p.m., about an hour after the shooting, Robinson was seen in surveillance footage returning to the home on South Hale, still wearing the gray sweatshirt and sweatpants, the complaint alleges.

On Feb. 14, the FBI and Chicago police arrested Robinson on a federal warrant issued by U.S. District Judge Edmond Chang and executed a search warrant at his home. During the search, agents found a gray hooded sweatsuit with a black stripe down the side of the pants legs matching the one the shooter was wearing, the complaint alleges.

Records show that at the time of his death, Vaughn faced charges of being an armed habitual criminal. He was arrested in September by Chicago police who were trying to break up a South Side dice game, according to Cook County court records.

Chicago police alleged that Vaughn resisted arrest and was found with a loaded pistol in his pocket that had been altered with a device that made it fully automatic.

Vaughn had been on electronic monitoring pending trial. At his first status date after the shooting, Cook County Judge Joanne Rosado wrote on the court sheet: “Defendant not in custody. Defendant deceased.”

jmeisner@chicagotribune.com