According to the Kingsport Police Department, the alleged incident occurred around 1 a.m. Jan. 27 at the Valero located at 817 Lynn Garden Drive.
Authorities said an off-duty employee had just entered the gas station when a white male asked him to step outside and assist him with a vehicle.
Once outside, the suspect demanded money from the employee and threatened to shoot him if he did not comply.
When the employee told the man that he did not have any money, the suspect reportedly repeated his demand and threatened to once again to shoot him.
After being told a second time by the employee that he did not have any money, the suspect reportedly left the area around the back of the store.
The suspect allegedly had his hands concealed in his coat throughout the incident.
KPD said the investigation was ongoing and asked anyone with information on the suspect's identity or whereabouts to contact the Kingsport Criminal Investigations Division at (423) 229-9429.