A Casper man is accused of sexually forcing himself on a girl who was baby sitting his child.

Twenty-five year old Benjamin Marquez has pleaded not guilty to one charge of first degree sexual assault and one charge of third degree sexual abuse of a minor.

Investigators with the Natrona County Sheriff's Office say in middle December 2015, the under-aged victim was babysitting Marquez's infant child.

Marquez was at a holiday party followed by a birthday party at a bar, and then returned home with some friends for an after party.

The victim went to sleep on a air mattress in a bedroom, and says later that night, she woke up to a male on top of her having intercourse with her, adding that she felt overpowered by the male, but was able to push him off of her.

When interviewed, Marquez recalled blowing up the air mattress for the victim, but blacked out after that and remembered nothing else.

After comparing DNA samples taken off of the victim, and from Marquez, investigators say they found a match.

Marquez is free on $15,000 bond awaiting trial, and could face between five-to-50 years in prison on the first degree sexual assault charge, and up to 15 years in prison on the third degree sexual abuse of a minor charge if convicted.