A 66-year-old man was beaten on Monday by a group of teenagers who had been firing Nerf guns at riders at an MBTA station, transit police said.
Three members of the group were arrested later at a different station later on, MBTA Transit Police said Tuesday.
The incident began about 7 p.m. at the Downtown Crossing station, where six or seven teenage boys aged 14 to 16 pointed the toy guns and otherwise harassing and intimidating people, police said.
When the man was entering the Orange Line, the teenagers shot him in the head with the Nerf guns. He and the group exchanged words, then the teenagers attacked him, "punching him and throwing him against the wall," police said, ultimately sending him to the hospital for head injuries.
The group rode off on a Red Line train, with transit officers in pursuit, police said. The officers put members of the group in custody at the JFK-UMass station -- "they were causing a ruckus there as well," according to police.
The three teenagers who were arrested on an assault and battery charge were identified based on witness descriptions and video surveillance, according to police.
None of the teenagers were identified.