Alex Anthony Madrid has been arrested in her death and is held on suspicion of first-degree murder, kidnapping and sexual conduct with a minor, among other charges.
Court records indicate Madrid has not yet been appointed an attorney.
Mesa police Sgt. Tony Landato says detectives learned during their investigation that Madrid, who was a family friend, had previous inappropriate contact with the victim, something she only shared with friends. He says police had never been called to the home.
Madrid has a long arrest record and convictions for drug possession, theft and assault, among charges.