A convicted criminal considered a key suspect in the kidnapping and torture of a Northern Ireland businessman died from a suspected “cardiac event” after being handcuffed during his arrest, an inquest has heard.

Cyril McGuinness, known as “Dublin Jimmy”, was seen to smoke three cigarettes and drink a cup of tea while sitting on a sofa following his arrest at around 7am in the Buxton area of Derbyshire on 8 November.

Chesterfield coroner’s court was told McGuinness, who “already had a diseased heart”, collapsed 60-90 minutes later at the address on Rockfield Road and was pronounced dead at around 10am.

Police called an ambulance and attempted resuscitation immediately but the 54-year-old died almost three hours after his arrest.

The raid was part of a co-ordinated series of search operations, mainly focused on the Irish border area, linked to the brutal attack on the Quinn Industrial Holdings (QIH) director Kevin Lunney in September.

Lunney, 50, was abducted outside his home near Derrylin, Co Fermanagh, and taken to a horsebox across the border, where he was savagely beaten.

His attackers broke his leg, sliced his fingernails and face with a Stanley knife, carved QIH on his chest, and doused the father of six in bleach.

The attack was the most serious in a five-year campaign of intimidation targeting the companies and directors that now control the business portfolio built up by the fallen tycoon Seán Quinn, once Ireland’s richest man.

The opening of the inquest on Monday was told “no trauma” had led to McGuinness’s death and it was likely that he had died as a result of a cardiac event due to an “already diseased heart”.

Giving evidence at the inquest on Monday, DS Steve Simmons said the death had been automatically referred to the Independent Office for Police Conduct (IOPC).

Outlining the events leading up to McGuinness’s death, Simmons said: “The circumstances are that Derbyshire police attended an address in Buxton at the request of the Police Service of Northern Ireland.

“Mr McGuinness was arrested at about 7am, was placed in handcuffs, and approximately an hour to an hour and a half later he collapsed.

“During that time there was a search of his property.”

The senior coroner for Derby and Derbyshire, Dr Robert Hunter, told the officer it was his understanding that McGuinness “was sat on the sofa and had three cigarettes and a cup of tea”.

Simmons added: “Police present began resuscitation straight away and contacted the ambulance service.

“Mr McGuinness was pronounced dead at 9.55am.”

Hunter adjourned the inquest until the conclusion of the IOPC investigation.