Osbourne left school at the age of 15, and after trying out, but failing several jobs, he became a criminal, often earning money by robbing stores and warehouses. He once served six weeks in prison.
Kennedy was on a diplomatic visit to the British capital, when, leaving a cinema with his wife and children, he was suddenly shot in the back by 19-year-old Osbourne. After arrested, Osbourne was interrogated by the police. He stated that he had seen "a rich fella, probably a shite tory with his pretty whore, coming out of a movie theatre", and thought about shooting and robbing him, not knowing about his identity. He stated that he had no political intentions whatsoever, and hadn't even planned to kill him, "just shoot the hell outta him".
Although the police had many doubts about his version, Osbourne was not interrogated any more until his death. He was transferred to Pentonville Prison, and investigation and further interrogations were planned. However, Osbourne committed suicide in prison, less than two months after the murder, and the real facts behind the event remained unknown ever since. Many conspiracy theories have been circulating ever since, about Osbourne being a Soviet or Cuban agent, etc. A psychological study claimed that Osbourne was mentally unstable, even heavily psychopathic at some points. It is also widely known, that he often called himself "Iron Man" and had visions about a nuclear war.