During his 39-year-career as a garda, Detective Inspector Eamon O' Reilly was involved in some of Ireland's most notorious cases and dealt with some of the country's most evil criminals.
But one of the most twisted individuals whom the hugely respected detective, who retired this month, ever dealt with was vicious serial rapist Michael Murray.
The 59-year-old garda from Co Mayo was just one year into his lengthy spell in his job as a detective inspector when he took charge of the investigation into Murray, who went on a depraved rampage of sex attacks over a six-day period in September, 1995.
The attacks took place in Dalkey, Killiney, Monkstown, Ranelagh and Rathmines. Murray also attempted to strangle some of his victims before he was brought to justice by Eamon O' Reilly.
In an exclusive interview with the Herald, Mr O' Reilly explained that he was aware of Murray when the rapist arrived back at his Sallynoggin home as soon as he came back to Dublin after serving a lengthy jail term in England for a rape.
"I always believed in working very closely with the local community and in this case it paid major dividends. A local contacted me to tell me that Murray was back in the Sallynoggin area and that he was not a nice guy. I decided to keep a close eye on him.
"Shortly after this, in early 1995, I was on duty driving home after a day in court when I saw him exposing himself to a five-year-old girl and a three-year-old boy. It was a terrible sight -- I arrested him and he was prosecuted for the offence," Mr O' Reilly said.
After getting a four-month jail sentence at Dun Laoghaire District Court in April, 1995, Murray was a free man to carry out his evil reign of terror just five months later.
During this terrible period, Murray raped four women and sexually assaulted two others in just six days.
Mr O' Reilly had nominated Murray as a suspect as soon as he heard about the first attack.
He told the Herald: "These were all really terrible attacks but the worst incident was the young woman who was attacked in Ranelagh. I have so much admiration for that woman -- she was so lucky not to be murdered by Murray.
"She played him cool even though she was going through the most horrific ordeal imaginable.
"Eventually, he tried to strangle her and I will never forget the statement that woman made about that -- it contained the most graphic details of someone who thought they were breathing their last breath."
Michael Murray was arrested on September 23, 1995, and after initially denying everything, eventually made a statement about his crimes.
Mr O' Reilly was involved in arresting and interviewing Murray and later gave key evidence at the rapist's trial in October 1996, when Murray was handed an 18-year-jail sentence.
"Yes, I interviewed him. He was a very strange guy -- not your regular criminal at all. He denied everything at first and then admitted his role but he never explained why he committed those crimes.
"He was always a loner and I know that in prison, he never mixed with anyone. I found out that he was using the prison gym every day which meant that he was a super-fit guy by the time he got out of jail in 2009.
"I believe that this fact makes him an even more dangerous prospect. In the case of Michael Murray, I can honestly say that leopards don't change their spots and this man is still a danger," the retired detective explained.
During his distinguished career, Mr O' Reilly was involved in a number of major murder investigations including that of a gay RTE set designer who was murdered in his flat on Brighton Avenue, Monkstown, South Dublin, on January 21, 1982.
The victim Charles Self (33) had knife wounds to his chest and neck and a tartan scarf around his neck.
Mr Self who originally came from Glasgow, was involved in the design of a number of RTE shows including the Late Late Show, then hosted by Gay Byrne.
The garda cold case team began an investigation into the murder earlier this summer and are understood to be examining a number of new leads
At the time of the murder, Mr O' Reilly was a detective based in Kill-of-The-Grange and was very familiar with the case.
"This man was stabbed 13 times at the top of the stairs of his home and then his body was rolled down the stairs of the property. At the time, we had a strong idea who was responsible.
"There were two main theories -- one is that he picked up the wrong guy and the second was that he was the victim of a gay bashing. Looking back on it now, I believe it was an inside job -- that Mr Self was murdered by someone who knew him," Mr O' Reilly explained.
Mr O' Reilly was also the lead investigator in the Dalkey House of Horrors case which emerged when local woman Cynthia Owen gave him a statement which outlined how she was routinely raped by her father, sexually abused by her mother, and drugged with tranquillisers so a group of strangers could have sex with her.
Cynthia had a baby when she was 11 but her mother stabbed the newborn girl to death with a knitting needle, dumped the body in a lane in Dun Laoghaire in 1973, and told Cynthia to forget it ever happened.
"I interviewed Cynthia Owen for two days but the case was already 22 years old when I first took it on and it was a very difficult case.
"I arrested her father and mother Peter and Josephine Murphy (both now deceased) -- I had known Peter Murphy Snr from my time working in Dalkey -- he was an easier person to deal with than his wife.
"She is the only person that I ever arrested on suspicion of murder that just laughed in my face.
"I sent a file to the DPP on five separate occasions in relation to that case but a prosecution was never recommended."
With his retirement years now starting, dad-of-two Mr O' Reilly is hoping to spend more time with his wife Anne and the rest of his family as well as making more visits to his native Co Mayo.
He also intends to continue his charity work with the local Lions Club and is planning a well deserved holiday break.