A Derbyshire man died in police custody hours after being arrested following the death of his mother.
Chesterfield coroners' court heard Peter Birds suffered a 'cardiac event' in his cell - possibly caused by the stress of losing his mother and his subsequent detention.
Coroner Kathryn Hayes said 51-year-old Mr Birds was arrested in Matlock at around 2pm on November 23 last year 'for an offence upon his mother', who had died 'a day or so before'.
Mr Birds appeared to be drunk and was taken to Buxton police station where it was decided he should be seen by Dermot O'Donohue, a healthcare professional, to be assessed.
In a statement read out in court today, Mr O'Donohue said: "I felt he was fit to be interviewed and fit to be detained.
"He had capacity to answer questions."
Mr O'Donohue added: "He said he had a problem with his heart valve.
"There was a possibility he was an alcoholic and he was clearly upset and very emotional - he kept referring to his mother dying.
"Due to this, I left some diazepam with the custody staff in order to ease any possible alcohol withdrawal and to ease his emotional upset."
The court heard single Mr Birds - who lived at Mawstone Lane, Youlgrave, and cared for his mother - was later interviewed by police then taken to a cell to sleep.
He was placed on 30-minute observations and these were carried out as required, the inquest was told.
During one of the observations, a prison officer heard Mr Birds talking in his sleep.
He said, 'she’s dead'.
At 2am on November 24, a police officer checked on Mr Birds and noticed his right hand was 'very white' and he was not moving.
Despite resuscitation attempts by police and paramedics, Mr Birds was pronounced dead at 2.40am.
A post-mortem examination concluded Mr Birds died of coronary artery atheroma and left ventricular hypertrophy.
There was no evidence that alcohol played a part in his death.
Recording a conclusion of death by natural causes, Ms Hayes said: "In people with heart conditions, stress or exercise can cause them to become ill very quickly.
"Undoubtedly he would have been stressed and upset by the events of the day and the death of his mother.
"It's entirely possible that this stress led to sudden onset of a cardiac event related to his cardiac disease."
Ms Hayes said Mr Birds' 'treatment during his arrest and detention was appropriate as per my investigations' and she did not criticise anyone.
"His death was a natural event," she added.
"It's a very sad case and my thoughts are with Mr Birds' family and friends."