FAIRFIELD - A 73-year-old Fairfield man is being charged with sexually assaulting a teenage boy more than a dozen times.

Police say the alleged crimes happened over four years. They say an alert parent tipped off police.

According to officials, the man, Robert Purcell, denies the charges. However, police say a voluntary interview and evidence proves Purcell assaulted the minor.

Police say Purcell knows the victim and that it was not a random act. Authorities are also investigating alleged additional crimes by the suspect against the same victim.

Police say they are grateful the family came forward and suggest other people who think they've been a victim of sexual assault do so also.