San Francisco- An HIV-positive San Mateo County man will stand trial for allegedly raping his young stepdaughter three times while knowing he was infected with the virus that causes AIDS, authorities said.

Frederick Torralva, 53, faces charges of statutory rape, committing lewd acts with a child under 14 and committing continuous lewd acts with a child.

There is an additional allegation that he assaulted the girl with a dangerous or deadly weapon — the HIV virus, which can be transmitted through bodily fluids such as semen. If Torralva is convicted, and the additional allegation proven, it would make the sentencing penalty more severe.

Torralva, who lived with his family in unincorporated Redwood City, pleaded not guilty in San Mateo County Superior Court on Wednesday and remained behind bars in lieu of $1 million bail.

The girl reportedly has tested negative for the virus.

San Mateo County Deputy District Attorney Gregory Devitt said that the most recent alleged rape occurred on June 27, after the girl’s mother left the house. She quickly returned because she forgot her keys and found her husband having sex with her daughter. The woman told authorities that when she confronted him, Torralva admitted raping the girl three times. It is unclear when the two other alleged incidents took place.

If convicted of the charges, Torralva could face 15 years to life in prison, Devitt said.