"In 1995, someone called the FBI in New York offering information about an alleged plot to kidnap Kennedy in New York City, according to an FBI report dated July 13, 1995. The caller told the FBI that the alleged kidnappers 'had determined that Kennedy rode a bicycle in Manhattan and did not have any bodyguards,' the report says."
https://www.latimes.com/archives/la-xpm-2000-jun-20-mn-42953-story.html
FBI Tells of 3 JFK Jr. Kidnapping Threats - Los Angeles Times
Report: The first occurred while Kennedy was in elementary school, the most recent was four years before he died at age 38 in a plane crash.
https://www.latimes.com/archives/la-xpm-2000-jun-20-mn-42953-story.html