Shawn Johnson, Alleged Stalker Appear in Courtroom

Olympic gold medalist and "Dancing with the Stars" champion Shawn Johnson came face-to-face with her accused stalker in a Los Angeles courtroom Thursday morning, describing how she was frightened by the whole ordeal.

Robert O'Ryan, 36, was arrested March 23, 2009 after driving from Florida and allegedly jumping over a fence at the television studio where Johnson was preparing for an episode of "Dancing With the Stars."

Police searched O'Ryan's car and found two loaded guns, duct tape, a wooden club and handwritten poetry by O'Ryan to Johnson. In one passage, O'Ryan wrote "no matter what happens I will always love you."

Prosecutor Wendy Segal asked the 18-year-old Johnson if she knew O'Ryan and how she felt after reading some of the poetry.

"I didn't know him. He was a stranger to me. To see someone with that kind of obsession made me really scared," Johnson said.

Johnson -- who said she was "very nervous" on the stand -- testified that she considered quitting "Dancing With the Stars" early and going home to Iowa after the incident.

"I heard he'd said he was coming to L.A. to marry me, that I was the mother of his unborn children," Johnson said.

Johnson and her parents eventually decided to continue on "Dancing with the Stars" and instead alter her normal routine -- changing vehicles, hotels and cancelling all personal appearances.

O'Ryan is facing two felony counts -- one count of stalking and another for burglary after allegedly jumping over the studio fence. He faces two misdemeanors for carrying a loaded shotgun and .45 caliber handgun in his car.

He has pleaded not guilty by reason of insanity and has waived a jury trial. If he is convicted, the judge hearing the case will decide whether O'Ryan is legally insane.

O'Ryan had no visible reaction when Johnson walked into the courtroom. Johnson testified for about 24 minutes before she was dismissed by the judge. In court Tuesday, public defender Judith Greenberg tried to demonstrate that O'Ryan cooperated with the police investigation by telling investigators where he had hidden weapons in his car and by providing them with the combination to a safe that contained gifts for Johnson -- a picture frame and a small wooden purse.

The trial is expected to end by Friday.

O'Ryan could get close to six years in state prison if he is found guilty and sane or, potentially, the rest of his life in a mental hospital if he is found guilty and insane.

Earlier this week, O'Ryan told the judge he understood that gamble and was willing to move forward with his insanity plea.

His public defender has said previously that her client had no personal contact with Johnson, although the district attorney claims O'Ryan was willing to do anything he could to get close to her, even if it meant breaking into the Los Angeles TV lot where "Dancing with the Stars" is filmed.

Shawn Johnson's Alleged Stalker on Trial

Police said they believed he had driven cross-country from his home at the Osprey RV Park in Yulee, Fla., to Los Angeles to see Johnson.

Five days before the arrest he had been pulled over in Alabama, and the dash-cam video of the traffic stop recorded him telling the police officer that he intended to "try to get her [Johnson] to marry" him.

"I know if sounds a little bit crazy, but my, uh, intuition tells me that we're gonna have a beautiful relationship together," O'Ryan told the policeman.

During the 29-minute stop, O'Ryan mentioned Johnson at least three times.

When the policeman asked O'Ryan where he was headed, O'Ryan said "California" and identified Johnson as "an Olympic gymnast. ... She's on TV now."

"I'm meeting her there and, uh, I'm going to try to get her to marry me," he said.

The Alabama policeman issued O'Ryan two tickets, one for not having insurance and the other for an expired license plate.

O'Ryan was a former Olympic hopeful before an injury caused extreme depression, a friend told ABC News.

He reportedly lived in the Florida RV park for less than a year and was considered a "loner" to neighbors.

"He didn't seem to associate with too many people," neighbor Dennis Cronin told ABC News' Jacksonville affiliate WJXX.

"He was just weird," another neighbor, Lorynn Thomas, said.

It's a different picture than a friend of O'Ryan's painted of the University of Florida graduate.

O'Ryan graduated with a degree in engineering and even tried out for the Olympic rowing team, but hurt his back and became extremely depressed, the friend said.

Larry Robinson, who co-operates the RV park, acknowledged O'Ryan's back injury and said the man had trouble walking but turned down all offers to help.

"He was real independent," Robinson told The Florida Times-Union. "I was going to take his mail to him ... but he said, 'No. I don't want no help.'"

O'Ryan has no criminal record in Florida.

ABC News' Alex Stone contributed to this story.