"Patrons who came in to make a purchase didn't see a clerk, so they checked around and found her in the back of the store," Athens-Clarke police Capt. Clarence Holeman said.
Hall, a single mother with an 8-year-old daughter and two months pregnant, already was dead from her wounds, he said.
Officers found signs of a struggle in the office, but they didn't know as of late this morning if robbery was the motive, he said.
"We have to wait on an inventory to see if anything was taken, so right now we can't say, but we're leaving it open as a robbery, " Holeman said.
Investigators think more than one person was involved, but Holeman wouldn't explain why.
The suspects took a videotape from the store's surveillance system before fleeing, he said.
Detectives are trying to find outdoor surveillance cameras at surrounding businesses that might show the killer or killers entering and leaving the convenience store.
Hall's slaying was the second in two days on Athens' westside.
Kenneth Omari Wray, a 30-year-old Athens-Clarke public works employee, was gunned down outside his home on Knottingham Drive Tuesday.
Police don't have any suspects in that slaying.