The father of a victim of an alleged sexual assault is accusing the Alberta Children's Hospital of a cover up.

Police were called to the hospital on Wednesday, September 7, 2011 for a complaint of a sexual assault on a 13-year-old boy.

The Child Abuse Unit was contacted and launched an investigation.

It was during the investigation that police learned of a second victim, who was allegedly sexually assaulted during his stay at the hospital in August 2010.

The second victim was 11-years-old at the time of the alleged offence.

On Friday, police charged Drew Legary, 42, a nurse at the hospital, with two counts of sexual assault.

The father of one of the alleged victims says it was only after he went to police that the hospital admitted he wasn't the first parent to complain.

Legary stopped working at ACH after the accusations were made in September.

It is not known whether Legary was suspended, fired, or quit.

The father of the alleged victim says he has also been touch with the family of the other alleged victim.

He says that family told him they complained to the hospital after the incident with their son in August of 2010 but that the hospital never followed up with them after they went home.

"I'm disgusted beyond belief. I feel that I was lied to. I feel that this could've been prevented," said the father who can't be named to protect the identity of the child.

Alberta Health Services isn't commenting on the case and says it is before the courts.

AHS also won't say if they have any sort of investigation or disciplinary process in place or if they were aware of the initial complaint.

Legary will appear in court to answer to the charges next month.