WOBURN, Mass.  —  A Medford man has been sentenced to life in prison for raping two deaf children.

Philip Duffy was convicted in August on multiple counts of child rape, indecent assault and battery, and posing a child in a state of nudity.

On Tuesday, Middlesex Superior Court Judge Diane Kottmyer sentenced Duffy to life in prison.

Prosecutors said the 48-year-old Duffy knew the victims and targeted them because they were young and vulnerable. They said one victim was abused for nearly four years, beginning when she was 12.

Middlesex District Attorney Gerry Leone called the life sentence "appropriate," and said he hopes it sends a message to those who commit crimes against children.

Duffy's lawyers did not immediately return a call seeking comment.