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 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 7 o’clock in the Buxton area of Derbyshire on November 8.

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 Quinn Industrial Holdings (QIH) director Kevin Lunney in September.

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

Lunney kidnap suspect died from a suspected 'cardiac event' Credit: UTV

The attack was the most serious in a five-year campaign of intimidation targeting the companies and directors.

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

Giving evidence at the inquest opener on Monday, Detective Sergeant Steve Simmons said the death was automatically referred to the Independent Office for Police Conduct (IOPC).

Outlining the events leading up to McGuinness's death, Mr Simmons said,

"The circumstances are that Derbyshire Police attended an address in Buxton at the request of the Police Service of Northern Ireland.

Detective Sergeant Steve Simmons

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".

It’s understood police present began resuscitation straight away and contacted the ambulance, however, Mr McGuinness was produced dead just before 10am.

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