Night manager Gregory Smith was the last person to leave the Applebee’s in Fayetteville on Sunday morning, locking up around 3 a.m.

But the 27-year-old never made it out of the parking lot.

Fayetteville police Lt. Mike Whitlow told The Atlanta Journal-Constitution that authorities got a call from Smith’s girlfriend around 6:30 a.m. She told police that, after Smith didn’t come home, she went to the restaurant on North Glynn Street herself.

She found Smith dead inside his vehicle.

Whitlow said responding officers found that a gunshot had pierced the driver’s side window. Shell casings were also found in the parking lot, leading authorities to believe the shot was not self-inflicted.

“The shell casings in the parking lot indicated that there were other people involved in this,” Whitlow said.

Whitlow declined to speculate on what may have preceded the shooting. He said the Applebee’s has surveillance cameras but that they did not capture the incident. Police were canvassing nearby businesses in hopes of finding additional footage.

Smith’s Facebook page, which listed him as a graduate of Benjamin Banneker High School, was filled with tributes Sunday as news of his death spread.

“Not only were you the best manager ever,” one woman wrote, “but you were also an amazing friend.”

Wrote another: “So sad to hear this happened to such a good person.”

Attempts to reach Smith’s family were not successful Sunday.

Authorities want to speak with anyone who was in the area of the Applebee’s between 3 and 3:15 a.m. Anyone with information is asked to contact Detective Scott Gibson at 770-719-4226.

Whitlow said Applebee’s is offering a reward for information leading to an arrest and conviction. The amount of that reward was not released, but Whitlow said it would be “significant.”