A good Samaritan tackled a 17-year-old from Dorchester Wednesday after the teenager allegedly robbed a woman of her cellphone while she was on Boston Common, Boston police said.
At about 7:40 p.m. Wednesday, police were flagged down while patrolling on Boylston Street near the Common, police said.
Officers spotted a teenager running through the park, pursued by a man and a woman, police said.
A second man appeared and tackled the teenager , giving officers the chance to make an arrest, police said.
Police said the teenager allegedly robbed the female victim of her phone while another suspect came from behind and stole her laptop.
A search for the second suspect was unsuccessful, police said.
During the struggle for the electronics, the teenager allegedly brandished a knife, threatening to stab people, before running away.
The teenager was pursued by the victim and another man. The good Samaritan suddenly appeared and tackled the suspect.
Police said they recovered a folding knife, a lighter, and a watch on the teenager after he was taken into custody.
The teenager was charged with armed robbery and assault with a dangerous weapon, police said.