DNA evidence has provided a link between two sexual assaults on young children four years apart, police say.

The first attack occurred Oct. 20, 2013, inside the apartment building at 429 Barrie Street in Waterloo. According to Waterloo Regional Police, a four-year-old girl had been playing with friends outside the building. When she went inside for water, she was allegedly sexually assaulted in a stairwell by a man she did not know.

Police believe the same man is responsible for the sexual assault of a six-year-old girl at 318 Patricia Avenue in Kitchener on Oct. 27, 2017. That attack also happened in a stairwell, as the girl was coming in from playing outside.

The man is described as being white, slim and 5’10” to six feet tall. Police believe he has spent time at 318 Patricia or in the area around the building in the past.

“We’re hoping that this individual turns himself in,” Insp. Mike Haffner said in an interview.

Police say they want to hear from anyone with information about either attack.