Boston police are acknowledging that a mistake by a 911 dispatcher delayed the response to an elderly man who had been robbed and beaten.

It took 35 minutes for officers to reach the 76-year-old man, who was bleeding from the head after being attacked April 20 in the city's Hyde Park neighborhood.

Police spokeswoman Elaine Driscoll says the dispatcher assigned a low priority to the April 20 call because the assailant had already fled the scene. She says the call-taker "misjudged the gravity of the situation."

Driscoll says the dispatcher will be retrained and could face discipline. The department also said it will move up a previously scheduled training course for all 911 call takers and dispatchers, and have supervisors monitor more of the calls.

Police Commissioner Edward Davis called the victim of the attack to apologize.

The man, who did not want his name used, told The Boston Globe he was concerned about the training dispatchers are receiving.