1979: IRA bomb kills Lord Mountbatten

Read more here:
" The attack has called into question the security arrangements surrounding the Mountbatten party. Lord Mountbatten never had a bodyguard.

The local police kept watch on Classiebawn castle for the one month a year Lord Mountbatten spent there.

But his boat was left unguarded in the public dock in Mullaghmore where it was moored. ...
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Later in the article:

" Thomas McMahon, 31, was convicted of the three murders.

He had been detained in the area by police on suspicion of driving a stolen car two hours before the bomb went off.

McMahon was set free in 1998 under the Good Friday Agreement. "