Former head of Special Branch and Assistant Chief Constable of the RUC John Whiteside MBE, OBE who was closely linked with British intelligence during the Seventies, has died aged 88.
Mr Whiteside, a father-of-three, who spent most of his life in Belfast, died suddenly from an aneurysm on Monday after he became ill last Thursday.
His death has left his two sons, daughter and wider family circle in shock.
The former senior RUC officer was born in Londonderry in 1930 and went on to join the police force when he was 18 years old.
First stationed in Katesbridge in Co Down, the dedicated RUC man rose up the ranks throughout his career.
He spent some of his formative years working around Magheralin and Moira before going on to work in the CID in Coleraine.
He married his late wife Hester in 1954 and they went on to have two sons, Ronald and John, and a daughter, Diane.
Mrs Whiteside passed away two years ago, aged 84.
After spending several years in the CID working between Coleraine and Belfast, Mr Whiteside was transferred full-time to the city where he later became a Detective Sergeant in Special Branch.
In 1979, he was stationed at the Knock Road Headquarters where he was deputy head of Special Branch and in the Eighties, he was promoted to Assistant Chief Constable.
He spent his last four years of service in this post before retiring in June 1988.
Like many security forces families, the Whitesides had to be vigilant around their home and make daily checks of their vehicles.
His daughter Diane Horner, a mother-of-two, said: "He didn't really like to talk about his work during the Troubles at home.
"He wanted to try and leave that at work and enjoy downtime with the family."
Among some of his proudest moments, Mr Whiteside was awarded an MBE in 1977 and an OBE in 1983.
Diane added: "He didn't speak about them, he was very honoured to receive them but he was very private and humble.
"He didn't like to draw attention to himself."
With four grandchildren and four great-grandchildren, he was kept busy throughout his retirement years.
"He was still living independently until he went in to hospital last Thursday," Diane continued.
"After his retirement he played golf, took up bowls and it allowed more time for he and mother to do some travelling.
"They were married for 62 years, he missed her terribly after she died.
"His death was a shock, particularly when things took a turn for the worse so suddenly.
"He was a man of great faith," she added.
A service of thanksgiving for the loving father, grandfather and great-grandfather will be held tomorrow at 10.30am in Belmont Presbyterian Church, in east Belfast.
Family flowers only, donations in lieu, if desired, to the MacDermott Unit at the Ulster Hospital, Dundonald.