Convicted murderer Fred McClenaghan collapsed twice in prison before his death from a ruptured brain aneurysm.
An inquest into the death of the 57-year-old started today in front of a coroner but minus a jury due to coronavirus regulations.
McClenaghan had served one year of a 13-year sentence in Magilligan prison for the murder of his former partner Marion Millican (51) before he died at the Royal Victoria Hospital on October 21, 2018, five days after collapsing in jail.
McClenaghan, from Magherafelt was found guilty of the murder of Ms Millican - a mother of four - at a Portstewart launderette, where he shot her at point blank range in 2011.
While initially denying the charge against him - McClenaghan claimed Ms Millican's death was the result of an attempt to take his own life - he later admitted killing her.
During today’s hearing, McClenaghan’s sister and next of kin Eleanor McKee, who appeared remotely, told the court the deceased came from “a loving Christian family”.
In a statement that was read out Miss McKee said her brother “was suffering from mental health issues prior to the incident that led to him being imprisoned” and she told how she visited him every fortnight “and spoke to him most days on the phone”.
Prior to Ms Millican’s murder, Miss McKee said: “I feel he was neglected by (the health system) and the police” adding that the Police Ombudsman “is “aware of our grievances”.
She told the court that “his mood was very low and he wasn’t eating” ahead of his collapse in prison and she said “he was complaining of headaches”.
Ms McKee also said she had told prison staff she was worried about her brother’s health after her last visit as “he was a grey colour” and “I was really concerned about him that day”.
CCTV footage that showed McClenaghan collapsing twice within an hour in prison, was played to the court.
Initially, he fell in a corridor and a nurse attended him in a cell.
He then collapsed a second time in the ablutions room and, after another examination by the same nurse, was taken to Causeway Hospital by ambulance.
McClenaghan was subsequently transferred to the Royal in Belfast, where he died five days later following a ruptured brain aneurysm.
The hearing is expected to take evidence from a number of witnesses including members of the prison service and medical staff.
Previously, the murder trial had heard detail of how McClenaghan's relationship with Mrs Millican had been one which had been categorised by "violence".
It was revealed that at the time of her murder, Mrs Millican - who had separated with McClenaghan in December 2010 - was in the process of reconciling with her husband.
Ahead of today’s hearing, the coroner said she had decided to invoke the Coronavirus Act 2020 which “allows me to sit without a jury when the death occurred in prison and where it appears the death was caused by natural illness”.
The inquest continues.