Activist Malik Shabazz and other people got together Monday to pass out flyers with photos of the suspect and the victim, Denez Dupree.
Police said the suspect talked to Dupree and even gave him money outside of a Clark gas station on Dexter and Collingwood before he shot and killed him around 7:30 a.m. Oct. 3.
Panhandler Denez Dupree was murdered execution-style.
"I mean all I can say is Jesus Christ, this guy is a predator," Shabazz said. "This is ugly, this is vile."
Dupree frequented the gas station and would sometimes pump gas for people in exchange for change.
After the murder, police said it did not appear the suspect and Dupree knew each other.
"It just seems like a random execution for no reason and it's highly concerning for us," said Detroit Police Capt. James McGinnis.
The shooter, who fled northwest from the scene, is white, stands about 5 feet, 9 inches, and was wearing a puffer jacket, a hoodie, black pants, and black shoes. He had a backpack with bright yellow zippers.
Anyone with information is asked to call police at 313-596-2555 or Crimes Stoppers at 1-800-SPEAK-UP.