A police officer interrupted a robbery of the Walgreens store early Thursday morning, the second at the store in less than four hours.The officer entered the store around 5:45 a.m. to pick up surveillance video of the initial robbery, which happened at 2:15 a.m. at the 2710 Salem Ave. pharmacy in Dayton OH.While in line behind the suspect, the officer saw the suspect reach into the drawer and remove money. The officer drew his weapon and ordered the man, 55-year-old Donald Cotten, to the ground. A struggle ensued with the officer at a disadvantage, having drawn his weapon, Sgt. Moises Perez, head of the robber unit, said.“We wasn’t going to shoot the guy because he was unarmed,” Perez said. “The problem was getting the gun back into a secure holster.”Security video showed the officer fending off Cotten with one hand while holding his sidearm in the other. As the pair struggled Officer Joshua Campbell was able to holster his weapon and take Cotten to the ground. During the struggle, Cotten hit the officer several times in the head and face, dislodging the officer’s radio ear piece, breaking his communications with dispatch.Perez said the blows stunned Campbell for a moment.The video showed Cotten escaping Campbell and trying to get out the door before Campbell grabbed him again and took him down a second time just outside the drugstore’s entrance. During the struggle, Cotten repeatedly attempted to grab Campbell’s sidearm. Once on the ground, two drugstore employees rushed out an assisted Campbell in restraining Cotten, according to the police report.According to Perez, when dispatch was unable to reach Campbell after his initial report of a struggle, backup was sent with sirens and lights. It took officers about 5 minutes to reach the scene because of weather and road conditions.“In a situation like that it seems like forever,” Perez said. “Every minute seems like an hour.”Once in cuffs, Cotten was taken to a local hospital for a precautionary checkup then to the Montgomery County Regional Jail. He has been charged with aggravated robbery, assault of a police officer and robbery, according to Dayton Municipal Court records.Cotten had a hammer and box cutter in a backpack he was wearing, the sergeant said.The assistance of the two employees was of an “immense help”, keeping Cotten from getting the officer’s sidearm, Perez said.“We love the public. We always have backup, and we appreciate it,” Perez said of the assistance.Police said Cotten is not a suspect in the earlier robbery of the Walgreens.