It has been a trying month for two older people in Arlington, with separate robberies targeting an 87-year-old man and a 91-year-old woman, authorities said.

Robbers invaded the home of the 91-year-old on South 31st Street on Saturday after knocking on her door and claiming that they needed to do utility repairs.

Once inside, one confined her in a room, while the other ransacked the house. The two then fled and were at large.

In the other incident, which occurred June 14, the 87-year-old was grabbed by the neck and thrown to the ground in the 3800 block of North Ninth Street.

The robber grabbed the man’s wallet, took cash and fled, police said. But, they said, a witness came to the victim’s aid and gave a detailed description of the robber to police. They said they quickly seized someone at the Ballston Metro station.

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