MISSOULA, Mont. -

William Sandel, 28, of Missoula, pleaded not guilty to charges of aggravated assault, sexual assault and attempted sexual assault in Missoula County Court Tuesday morning.

Sandel is accused of attacking a woman earlier in July by the Higgins Ave. Bridge. Charging documents say he admitted to grabbing her from behind and pushing her to the ground. Prosecutors say Sandel confessed to police he "thought about having sex with her but was too scared."

Sandel is also accused of pinching a woman's buttocks while she was on the Kim Williams Trail on July 5.

If he is convicted of all three charges he could face a maximum of 20 years in prison, one year in jail and a $51,000 fine. He will be back in court on August 12.