NASHUA -- A 55-year-old man has been arrested for allegedly sexually assaulting a woman last summer at a city residence.

Police say Roberto Saez, with a last known address of Burham Street, Worcester, Mass., allegedly engaged in a sexual act with an adult female while she was “physically helpless to resist.”

The crime occurred on the evening of June 30, 2011, however Saez was not arrested until this week. He has been charged with one count of aggravated felonious sexual assault, which is punishable up to 20 years in prison if convicted, according to police.

Saez was arraigned Wednesday at the Nashua District Court, and is currently being held on $10,000 cash or surety bail.