Transport Minister Kim Howells has been questioned by police over his admission that he destroyed records during the 1984-5 miners strike.
Kim Howells burned NUM records during strike in a 'panic'
Dr Howells, who was an official of the National Union of Mineworkers (NUM) at the time, went to police voluntarily.
In a BBC documentary earlier this year, the Pontypridd Labour MP said he was worried police would raid the union's office after a cab driver was killed taking miners to work.
Taxi driver David Wilkie died when two striking miners dropped a concrete pillar from a road bridge on to his car.
He had been taking two working miners under police escort to a Mid Glamorgan pit.
A South Wales Police spokesman confirmed that a 57-year-old man "had attended Pontypridd police station to be interviewed about comments he made in relation to the death of David Wilkie in 1984.
"He was released without charge - a report will now be submitted to the Crown Prosecution Service for consideration and advice."
Dr Howells is due to return to Pontypridd police station in six weeks time, when he will be told whether there will be charges against him.
Although Mr Wilkie's death was unrelated to any union work, Mr Howells said he felt the police would use the incident as an excuse to raid the NUM offices and get hold of their plans for running the strike.
Mr Howells explained that he had been tipped off about the tragedy by a reporter.
He spoke of his "sense of revulsion" as the death of the man and added: "I felt physically sick that someone had died as the result of the action of one of our members."
He said he then rushed to destroy records at the NUM Pontypridd HQ which he claimed would have only revealed NUM's strategy when planning their legal right to picket.
In an interview on BBC Wales' Good Morning Wales programme in January, he stressed that he felt a police raid on the offices could have compromised the strategy and that was the sole motive for his actions.
"I panicked" he said, "and destroyed a lot of historic documents."
The minister said that in November 1984 the strike had been going on for a long time and passions were running high among NUM members about miners who were abandoning the strike and returning to work.
Two men were convicted of the murder of Mr Wilkie, a charge later reduced to manslaughter. They were released in 1989.
The Miners' Strike documentary, which was broadcast on BBC Two, was an analysis of an historic and bitter dispute that created turmoil in thousands of lives and dramatically affected British society.