Michael Claywell, 42, was also charged with furnishing harmful material to a minor.
Officers said they learned that between March 1 and May 17, three of the victims and Claywell’s brother and sister-in-law lived together in a home in the 7400 block of West Superior Avenue.
Claywell is accused of molesting the three victims, ages 11, 13 and 14, living in the home and a 12-year-old neighborhood friend to one of the children.
Detectives said they were also able to determine that Claywell provided harmful materials to the children and that the children may have actually witnessed the molestations.
A search warrant was served on the home on Thursday and Claywell was interviewed by police detectives.
He gave police a full confession, investigators said.
Detectives are asking people who might have reason to be concerned about previous contacts with Claywell to call Phoenix police at 602-262-6151.