Crime Stoppers has increased the reward to $5,000 for information leading to the arrest in the murder of Mohamed Zokari, shot to death Nov. 4.
Zokari, 26, was found shot multiple times in the head and back while working at a Clark gas station at 7 Mile and Schoenherr on Detroit's east side.
The married father whose wife was pregnant with a second child was hoping to become an accountant.
Customers and friends at the gas station knew him as Mo - a nice guy who was willing to go the extra mile.
"I remember Mo as silly, cool, laid back good guy," said one customer.
Another customer said it may have been a robbery.
"He let you stand in there, get warm waiting on the bus," said resident Carrie Fason, who lives nearby. "Someone was probably trying to rob him. Everybody loved him."
Detroit police do not believe robbery was a motive. No money was taken and there may have been two different shell casings.
"Please come forward, you will be rewarded by God almighty," said Omer Abdi Nur, a community leader.
If you have information about the homicide, call Detroit police at (313) 596-5300 or Crime Stoppers at 1-800-SPEAK-UP.