A reporter who tried to give evidence to police about the 1974 Guildford pub bombings was "threatened" by officers, his father has told a coroner.
Charles King, whose son Rob, then 20, was among the first on the scene, has provided a statement to the coroner for a pre-inquest review later this year.
He said his son was held by police after he raised concerns about an alibi for one of the wrongly jailed Guildford Four and apparent police inaccuracies.
Rob King died in 2000 at the age of 46.
Two IRA bombs went off in Guildford pubs on 5 October 1974, killing five and injuring 65.
The Guildford Four - Gerry Conlon, Paul Hill, Patrick Armstrong and Carole Richardson - served 15 years before their release in what was seen as one of the worst miscarriages of justice in British legal history.
A pre-inquest review is to be held following a submission by KRW Law to Surrey coroner Richard Travers, which was made after the BBC obtained papers about the case.
In his statement to the coroner, Mr King said his son went to Guildford police station during the original trial in the 1970s and raised two concerns with officers.
- He had information supporting the alibi of Ms Richardson who said she had been "up North" at the time (KRW Law understand his reference to "up North" to mean north London)
- He insisted the first bomb went off at 20:30 - contradicting the time given by police of 20:50
Both points were referred to in a controversial five-year-long inquiry by Sir John May which ran from 1989, after the Guildford Four's convictions were quashed.
Sir John noted the timing of the first bomb had been reported inaccurately in the trial and at a 1977 appeal, but he backed the police account and recorded the inaccurate time as 20:30 and the correct time as 20:50.
However, Sir John went against officers when he looked at how police dealt with the witness for Ms Richardson. He wrote: "Surrey's approach was to seek to destroy her alibi rather than to investigate it with a truly open mind."
Rob King's concerns were reported in the Surrey Advertiser after the Guildford Four were released in 1989.
In a letter to the editor, he said he saw the apparently inaccurate timings as a "trivial quibble" that would not have affected the outcome of the case, but did show police errors.
BBC news broadcasts and Press Association wires from the time are no longer available, but in October 1974 The Times reported the first explosion as just before 21:00.
However, Charles King believes his son had already filed a report on the first bomb to the news wires by 20:50, adding that his son's concerns "there was something wrong" persisted for years and he felt his son had been "silenced".
He said his son - a Surrey Advertiser reporter who later worked for the Press Association, The Sun and The Daily Star - had been trained to report accurately and had tried to give the police information, but was "threatened" with detention.
"He was definitely silenced, really threatened," Mr King said.
"They wouldn't let him go. He said he wanted to go. He wasn't just threatened with detention.
"He wasn't arrested, but he was kept in the station until he agreed not to divulge anything."
Mr King said his son was pressed on where he got the information from but refused to reveal his sources.
In response to Mr King's claims, a Surrey Police spokeswoman said "through the evidence we have reviewed both at the time and in more recent years, we believe the incident happened at approximately 20:50".
She said calls were not recorded by Surrey Police in 1974 and it would not be appropriate to release a copy of notes taken at the time while a hearing was pending.
Surrey Police await decisions by the coroner and could not comment further, she added.
Carole Richardson's family and lawyers declined to comment.