LYNN – Two undercover Lynn police officers patrolling the streets near a Western Avenue doughnut shop Saturday are credited with helping to capture an armed robber after they watched him hold up the shop, according to police.Michael R. Reed, 29, of 12 Avenue A, Lowell, was arrested and charged with armed robbery while masked, assault with a dangerous weapon, resisting arrest and five default warrants. He was ordered held Tuesday on $75,000 cash bail by a Lynn District Court judge.Officers Ross Panacopoulos and Paul Holey, who are assigned to the LPD Special Investigations Unit, were driving an unmarked vehicle on Western Avenue near the General Electric plant when they noticed a man in the parking lot of Honey Dew Donuts tightly pulling the strings of his sweatshirt over his face and pacing back and forth, police said.After the officers observed the man they both looked at each other and simultaneously said, “He’s going to rob the store,” according to a police report.The officers pulled into the parking lot of Red’s Bar and continued to watch the suspect. They say he lingered outside for about two minutes before he worked up the nerve to walk inside the doughnut shop at about 7 p.m.Once the suspect walked inside, the officers pulled their car into the Honey Dew parking lot but the perpetrator had already begun the robbery, police said.The suspect allegedly walked up to the 34-year-old female clerk, pulled out a replica Glock handgun and shoved it in her face. He then handed her a brown paper bag and demanded her to fill it with money.Before the clerk had a chance to do so, the two officers burst inside the shop and demanded the suspect to show his hands. However, he allegedly ran toward the back of the shop and dropped the gun in the process. Police later realized the weapon was a BB gun.Several other police units arrived and, after an intense manhunt through area backyards with the help of State Police and a police K-9, Reed was found hiding in a dumpster in the backyard of a home under renovation at 91A River St.Panacopoulos and Holey “made a keen observation of a robbery in progress,” said Lt. Dave Brown. “They did an excellent piece of police work.