Police arrested a 50-year-old Cambridge man they say robbed a female cashier at knifepoint at New World Gas at 1 p.m. yesterday.
Police charged Thomas Nolan, of 402 Massachusetts Ave., with armed robbery while masked, said Lt. Antonio Mele.
Police are not sure whether he is the same man who robbed three other stores in Waltham. In each case, the thief wore a mask.
One of the station's owners, who declined to give his name, said his sister was working alone, with no customers in the store, during the robbery.
"It was terrible," he said.
His sister had gone to shut the door because it was cold and windy out, when a man approached her, held a knife to her stomach and demanded money, he said.
The two walked to the register. He took the money, and he did not hurt her, the owner said.
The store's video surveillance showed a man wearing a white mask over his face and a dark blue sweatshirt, with the hood pulled over his head, walk across Main Street, into the store, point something at the young woman behind the counter, take money from the register, and flee the station.
"We have many cameras here, so we can capture every moment. It's really safe. This never happened here before because the street is so busy," said the owner, whose family has run the station and store for about five years.
As the robber fled the station, heading east on Main Street, the female clerk followed, shouting "thief," her brother said.
"We know a lot of our customers, and some of them went after him and caught him," he said.
Several police officers saw the man, who had fled on bicycle, at the corner of Main Street and Ellison Park, and took him into custody, Mele said.
His clothing and appearance matched the description given by the victim, Mele said.
Police also found a knife and an undisclosed amount of money on the ground near Nolan, Mele said.
The station owner said police gave him all the money that the man had taken, so the family did not lose anything.
Police are trying to determine if Nolan is linked to other recent robberies.
A masked man robbed the River Street Food Mart twice - on Nov. 2 and Oct. 28 - the Banks Square Shell Station on Oct. 26 and the Shah Dollar Store at 368 Moody St. three hours earlier on the same day.
In each instance, the clerk was a female, working alone, with no customers in the store, police have said.
Joyce Kelly can be reached at 781-398-8005 or jkelly@cnc.com.
