When Rodney Talbo Shelton II took a Megabus from Hampton, Va., to Philadelphia last June, he was armed with a 9mm handgun, prepared to commit a robbery, and willing, authorities say, to use the gun if necessary.

Three days later, at a quiet loading dock in Yeadon at 3:30 a.m., with the same gun in tow, they say, Shelton had the opportunity he needed: an older target, a secluded location.

Authorities say Shelton attempted to rob Thomas Childs, 63, a delivery driver from Aston, at the Ridgway Industries loading dock along Baltimore Pike. When Childs resisted, Shelton allegedly later confessed to a friend, Shelton fired two shots, striking Childs once in the back and killing him at the scene.

Shelton made off with barely $20 and Childs' cellphone before dropping them just yards away in a cemetery, officials say.

Now, a $20,000 reward has been posted in the hunt for Shelton, of Elizabeth City, N.C., wanted in the June 9, 2015, murder of Childs.

Childs' wife, Ginger, 62, said that while "it's not going to bring [her husband] back," she was relieved to learn that a suspect finally had been identified.

On Monday, Delaware County District Attorney John J. Whelan announced that an arrest warrant had been issued. Authorities believe Shelton is hiding in North Carolina or Georgia.

"He acted maliciously and callously," Whelan said.

Whelan said authorities conducted an intensive investigation during the last year to conclude Shelton was their suspect. Ultimately, Whelan said, the gun Shelton used, recovered at Fernwood Cemetery not far from Childs' phone and cash, helped investigators pinpoint him as a suspect.

A local woman with whom Shelton had contact told investigators that he had admitted to the crimes in April, and that he said he was high at the time of the shooting, according to the affidavit of probable cause.

Shelton faces charges that include homicide, murder, robbery, and possession of a firearm with an altered identification number, among others.

Shelton has had prior arrests in North Carolina, according to authorities.

cmccabe@philly.com 610-313-8113