The man behind a fake posting on the online encyclopedia Wikipedia that linked a journalist to the Kennedy assassinations has apologised.
Seigenthaler criticised the Wikipedia's reliability
Tennessean Brian Chase said he added to the entry to trick a co-worker.
The discovery of the fake data in journalist John Seigenthaler's biography started a debate about the online reference work's reliability.
The prank caused Wikipedia to change its policy so only registered users can create entries.
Mr Chase, who added the false information to the biography in May 2005, said he did not realise that the online encyclopedia was taken so seriously.
The fake information stated that Mr Seigenthaler Sr was linked to the assassinations of John and Robert Kennedy and that he had lived in the Soviet Union for 13 years. The entry has now been corrected.
Quoted in The Tennessean newspaper, Mr Chase said: "I knew from the news that Mr. Seigenthaler was looking for who did it, and I did it, so I needed to let him know in particular that it wasn't anyone out to get him, that it was done as a joke that went horribly, horribly wrong."
The fake data was added to shock a co-worker who knew the Seigenthaler family, said Mr Chase. He has now resigned from his job as an operations manager with a Nashville delivery company following his unmasking.
The fallout from the prank led Mr Seigenthaler to write an opinion piece for USA Today which sharply criticised the reliability of Wikipedia.
Mr Seigenthaler was a founding editor of USA Today who worked closely with John Kennedy and was a friend of Robert Kennedy.
The incident also led to a lot of unfavourable coverage of Wikipedia in newspapers and online.
Mr Seigenthaler said he would not take legal action over the entry and urged Mr Chase's boss not to accept his resignation.