Yesterday marked his final day in the New Zealand Police after a career which stretched back to 1974.
Det Sgt Roberts spent his entire policing career in Dunedin and had been with the CIB since 1978, gaining promotion to Detective Sergeant in 1984.
While he still enjoyed the job, he felt the time was right to move on.
"I love working the frontline and for the last two years I was seconded to something else and there’s a new generation of young cops and I don’t want my position to hold troops back and I can’t keep doing frontline policing forever and a day," he said.
"There’s nothing startling [behind the retirement], but 43 years is enough."
"We never had DNA. We never had cellphones. We only had portable typewriters. Uniform cars had lights but no sirens. CIB cars had no lights or sirens, apart from Starsky and Hutch pop-ons."
The advent of DNA profiling and computer forensics had made the job much more complex. When he started it was not unheard of for a murder trial to call only five or so witnesses. Now hundreds could be called.
He pointed to the 2001 conviction of Colin Bouwer for the murder of his wife, Annette, the year before as an example of the complexity of modern murder cases.
"It was probably the most complex one we have done in Dunedin," he said.
"The internet was in its early, early phases, so we had to learn really fast — like we always do.
"With the Bouwer one we did investigations in Scotland, England, France, South Africa, America, Germany and Australia."
Witnesses were flown from throughout New Zealand and the world to give evidence at the trial, in which it was proved Bouwer, the former University of Otago head of psychological medicine, administered a cocktail of drugs to his wife between September 30, 1999, and her unexpected death on January 5, 2000 to mimic the effects of a rare tumour.
While convictions came with a relief that police had got their offender, it was "always tempered by the fact that someone has died".
"I always feel for the family," Det Sgt Roberts said.
"We are there to do the investigation to the best of our ability for the family and the victims. We are the final warriors there for the families and victims.
"The ones you lose are always harder on the families."
He also spent 14 years in the armed offenders squad, attending infamous incidents such as David Gray’s murderous rampage through Aramoana and the brutal killing of policeman Senior Constable Peter Umbers near Ranfurly in 1990.
"They are all difficult. They are all different. All high-adrenaline," he said of AOS responses.
"I have jet-boated up the Taieri River in full armed offenders kit at midnight in a snow storm. We thought we were mad. We were cold but there was still six hours of police work to do."
While there had been "numerous things you don’t want to remember", he could not recommend a career in the police highly enough.
"It’s been a 43-year blast."
"I don’t know where it’s gone. I have abseiled from a helicopter, down buildings. I have gone in jet-boats.
"The whole works. The stuff normal Joe Bloggs don’t get to do.
"I would recommend the job to anybody."
He had no plans yet for his future and would not confirm his age, other than to say: "I’m too young to retire".
"I haven’t got anything planned in the meantime," he said when asked what was next.
"I’m leaving in a positive frame of mind and getting out in the fresh air.
"Getting rid of the work cellphone and being a normal citizen — which might be a bit harder."
