Two men walked into Richard's Variety, 145 Franklin St., about 12:55 p.m. Thursday, and while one of them waited by the door, the other approached the register, showed a gun and demanded money.
Detective Sgt. Dana Burrill said yesterday that the man who stayed by the door appeared to be acting as a lookout.
"He called to the other guy to wait, wait, a couple of times," Burrill said.
The robbers took $60 cash and several lottery tickets before leaving the store. They were described as being in their late 30s and wearing hooded sweat shirts.
It was the fifth robbery or attempt at the store in 19 years, store owners Richard and Sandra Sarbanis said.
Burrill said Haverhill detectives are working with police in Lawrence in an attempt to identify the man in the picture.
The two men are not suspects in the Jan. 2 robbery at Walgreens at 310 Main St. or the Jan. 7 robbery of the Sovereign Bank branch at 400 Lowell Ave., Burrill said. They are not considered suspects in Monday's armed robbery of the Walgreens pharmacy on River Street.
"We have a suspect in that robbery and hopefully we will soon have an arrest," Burrill said.
He said the suspect in the first Walgreens and Sovereign Bank robberies also is suspected of robbing a Sovereign Bank branch in Londonderry on Dec. 24.