Shawn Johnson's Alleged Stalker Robert O'Ryan Enters Insanity Plea

LOS ANGELES (CBS/AP) The Florida man accused of stalking Olympic gold-medalist and "Dancing With The Stars" champion Shawn Johnson has pleaded not guilty by reason of insanity.

Despite a judge's warning, Robert O' Ryan, whose trial began Tuesday, pleaded not guilty by reason of insanity to felony burglary and stalking charges.

If he is found guilty and sane, he could face nearly four years in prison and two years in jail; however, if O' Ryan can prove that he is in fact insane he could face an even longer sentence in a state mental hospital.

According to prosecutor Wendy Segall, O'Ryan drove from Jacksonville, Fla. to Los Angeles in an attempt to meet the gymnast. After he arrived at studio where the 18-year-old was performing on the reality television series "Dancing With The Stars," he jumped the fence, but luckily was stopped before he could get to Johnson.

The alarming behavior continued after Segall revealed that O'Ryan, who allegedly harbored a dangerous obsession to marry the gold-medalist, was packing heat - specifically a handgun and a shotgun.

A search of the alleged stalker's car turned up a few other personal items as well: a club, duct tape, a knife, and a bulletproof vest.

Meanwhile, defense attorney Judith Greenberg said that her client posed no threat to the Olympic athlete, but only wanted to protect her from harm. She claims he rushed to the set because voices told him that she was in danger and in need of protection.