Celebrity stalkers may seem like harmless nut cases on the evening newscasts, especially when comedians like David Letterman and Conan O’Brien use their own stalkers as comic fodder. But underlying the jokes is the reality that obsessed fans can turn deadly.

The topic is in the news again with the conviction of 37-year-old Jack Jordan of stalking and harassing actress Uma Thurman. The out-of-work lifeguard and pool cleaner faces up to a year in jail after a jury listened to Thurman's testimony that he was scaring her to death.

“Experts say celebrity stalkers may seem harmless, but remember Mark David Chapman began as a seemingly innocent stalker of John Lennon, and wound up his killer,” NBC’s John Larson observed in a report filed Friday for TODAY.

Chapman is the most famous but not the only example of a stalker who turned violent. John Hinckley became obsessed with actress Jodie Foster’s performance in “Taxi Driver” and began stalking her. When he failed in his attempts to win her affections, in 1981 he shot and nearly killed President Ronald Reagan because he thought it would get her attention.

And in 1989, Robert John Bardo killed the young TV actress he was stalking, Rebecca Schaeffer, co-star of “My Sister Sam.”

“The one consistent thing we find in the minds and the actions of celebrity stalkers is that these are individuals who create their own reality,” former FBI profiler Clint Van Zandt told NBC.

And sometimes, when they are finally rejected, stalkers can turn violent.

Plays for attention
Often, their attempts to get attention are accompanied by threats. Dawnette Knight, a stalker obsessed with actor Michael Douglas, sent threats to his wife, actress Catherine Zeta-Jones, threatening to “slice her up like meat on a bone.” Zeta-Jones testified at the trial that she nearly suffered a nervous breakdown because of the threats.

Others resort to different strategies. Masahiko Shizawa, a Japanese national, was deported after stalking Britney Spears by using such ploys as sending her sex toys in the mail. Shizawa hasn’t given up, though — he’s suing Spears because, he claims, her bodyguards caused him emotional distress.

Ambrose Kappos stalked singer Sheryl Crow, sneaking backstage to meet her and calling her his “spiritual twin.”

In 2000, a pizza delivery man, Dante Michael Soiu, was convicted of stalking actress Gwyneth Paltrow. Like many stalkers, he tried to reach her by going to the home of her parents.

Zack Sinclair was sentenced to three years in prison for stalking Mel Gibson. Sinclair had claimed that god told him to pray with Gibson, and that’s all he was trying to do.

Then there was William Lepeska, who became obsessed with tennis star Anna Kournikova. He decided that if he took off all his clothes, swam across Biscayne Bay to her house, climbed up on her deck and shouted, “Anna, save me!” he’d win her heart. He executed the plan perfectly except for one tiny mistake — he swam to the wrong house, was arrested and sent to a psychiatric institution.

Another tennis star, Monica Seles, in 1993 was stabbed and wounded by Gunther Parche during a match in Hamburg, Germany. Parche was a deranged fan of German star Steffi Graf and thought that he could help his favorite player by taking out her biggest rival.

TODAY Mark David Chapman, the obssessed fan who murdered ex-Beatle John Lennon.

Margaret Ray, who spent nearly a year in prison and another year in a psychiatric hospital after being convicted of stalking Letterman, had frequently visited his home, once spending the night sleeping on his tennis court. She committed suicide in 1998.

Even Jerry Lewis, the comedian who became a cult hero in France, had a stalker. Gary Benson was jailed after showing up at Lewis’ Las Vegas home with a pistol.

Whether potentially violent or just plain crazy, stalkers terrorize their targets. Thurman says that’s what Jordan has done to her, and she wants him put away after what she says are two years of late-night visits, calls to her family and e-mails to her father.

“In Thurman's case, her accused stalker's lawyer says the actress's testimony is 'over-emotional,’ ” Larson reported. “But court testimony included his client's history of mental illness, and threats to kill himself if couldn't see the actress.”

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