Hayes was also convicted of conspiracy to cause three additional explosions in 1992.
He would later be convicted of mafia association and conspiracy to murder.
Steve comes across to clear our table - it's the first time Mary has met someone convicted of conspiracy to murder.
He was convicted of conspiracy to murder and sentenced to 15 years.
The prosecution also requested the death penalty for those convicted of conspiracy in the case.
In 1964, he was convicted of conspiracy to commit sabotage.
At a subsequent Federal trial, he was convicted of conspiracy to commit murder.
They failed and all three men were convicted of conspiracy.
In 1968 he was convicted of conspiracy to aid resistance to the military draft.
He was convicted 19 years ago of conspiracy to bribe a city commissioner.