CALGARY -- Mounties have charged a 41-year-old man with sexually assaulting a pre-teen girl while serving a conditional sentence in the community for a similar offence.

Corp. Terry Hamelin said the accused and the girl lived near each other on the Eden Valley First Nation, about 70 km southwest of Calgary.

The pre-teen girl agreed to the sexual relationship, but it's illegal in Canada to have sex with anyone under the age of 16, he said.

"It was a consensual relationship, it's just that she's too young to consent," said Hamelin, adding he couldn't reveal her age because it would identify her to the small Native community.

"He ... was on a conditional sentence order where he did have to be in his house 24-7 -- she came to him."

The accused, who can't be named to protect the identity of the child at the small reserve, has been charged with sexual assault, invitation to sexual touching and sexual interference.

It's believed the sexual relationship began this past summer, said Hamelin.

Earlier this month, concerned residents at the reserve told Mounties about the ongoing sexual relationship.

Alberta Children Services also investigated and the girl, who was already in provincial foster care, was removed from her surroundings and placed into protective care.

Hamelin said the foster parents were not aware of the sexual relationship.

The accused had been serving a conditional sentence at home after being convicted this past spring of sexually assaulting a girl several years ago, said Hamelin.

"Why did they let him back out?" he said about the court system. "He got to go back into his community and all he did was re-offend."

The accused is set to appear in Okotoks provincial court tomorrow.

TARINA.WHITE@SUNMEDIA.CA