The death of a suspected Northern Ireland gang member in Buxton was 'most probably due to a cardiac event in an already diseased heart', according to a pathologist.
Cyril McGuinness, 54, was pronounced dead at Stepping Hill Hospital, Stockport, at 9.55am on November 8.
Earlier that morning, Derbyshire Constabulary officers had carried out a search warrant at Mr McGuinness' house on Rockfield Road, Fairfield, on behalf of the Police Service of Northern Ireland.
Mr McGuinness' inquest was opened at Chesterfield coroners' court on Monday.
Sergeant Steve Simmons, of Derbyshire Constabulary, told the court that Mr McGuinness was married and worked as a businessman.
He added: "Mr McGuinness was arrested at about 7am and placed in handcuffs.
"An hour to an hour-and-a-half later, he collapsed."
Dr Robert Hunter, Derbyshire's senior coroner, said: "I understand that during the search of his house, he was on a sofa and had three cigarettes and a cup of tea and suddenly collapsed.
"Police started cardiopulmonary resuscitation as soon as possible and contacted the ambulance service.
"He was taken to Stepping Hill Hospital in Stockport where he was pronounced dead at 9.55am."
Dr Hunter added that pathologist Professor Guy Rutty said Mr McGuinness' death was 'most probably due to a cardiac event in an already diseased heart' and that 'further tests are needed'.
Dr Hunter adjourned the inquest to a later date.
As reported last week, the Independent Office of Police Conduct is investigating following the death of Mr McGuinness, who was also known as 'Dublin Jimmy' and is one of the men suspected of the abduction, assault and torture of a Northern Ireland businessman called Kevin Lunney.