Lawrence police returned Monday to search for more evidence and conduct more interviews in the wake of an armed robbery Sunday evening at the Dollar General store, 1811 W. Sixth St.

But no new information was released, including whether the bullet fired into the ceiling from the robber’s handgun had been found.

“They are busy collecting as much information as they can,” police spokeswoman Kim Murphree said of detectives at the store.

No one was injured in the robbery, which occurred shortly before 6:30 p.m. An assistant manager at the store Monday said employees couldn’t comment on the incident.

The Dollar General robbery was one of two weekend store robberies. The first occurred early Saturday when a man armed with a knife robbed the Kwik Shop at 845 Miss.

A male clerk told police the suspect entered the store at 4:28 a.m. and demanded money. After the clerk complied, the suspect fled on foot with a second man who had remained outside.

In the Dollar General robbery, police are looking for a white man who is about 5 feet, 5 inches tall with a thin build. He was wearing a gray sweatshirt.

The Kwik Shop robber was described as a man 18 to 25 years old, 5 feet, 9 inches tall, and 175 pounds. His race was unknown. He was wearing a light blue hooded sweatshirt and dark pants.

The second man was 18 to 25 years old, 5 feet, 5 inches tall, and 150 pounds. He was wearing a gray sweatshirt.

Police don’t know whether the same people are involved in the two robberies, nor are they saying whether the March 10 robbery of the Conoco convenience store at 23rd Street and Haskell Avenue is connected.

In that robbery, a man armed with a handgun and wearing a black hooded sweatshirt took money from the Conoco cash register and ran away. That robbery took place in the afternoon.

“I think it would be too early to say anything like that, other than that they were wearing the hooded sweatshirt,” Murphree said of a possible link in all three robberies.

Anyone with information about any of the incidents is asked to call 832-7501 or the Crime Stoppers hot line, 843-TIPS.