He targeted Securicor drivers making collections and deliveries around Bradford, netting thousands of pounds, and was later joined by his son Barry to target other companies.
Derek Elener took no chances. Anyone who offered any resistance was brutally dealt with, and his son would soon show the same ruthlessness.
Three people were shot at almost point-blank range and a woman narrowly avoided being shot in the head, before Tasawar Hussain became the Eleners' final victim.
Forensic experts combed the scene of each and every attack, but found not one fingerprint. Each robbery was fully investigated, but yielded no DNA genetic evidence.
Only when police were faced with a murder inquiry did the critical links between the murder and a dozen robberies become clear.
Derek Elener, 65, was a career criminal who planned his moves meticulously and covered his tracks. He had worked as a Securicor guard for more than eight years, giving him valuable knowledge of company procedure.
He lived an unassuming life with his second wife in Wibsey, Bradford, and did little to draw attention to himself.
He lived in a style just above his legitimate income, knowing that flashing his cash would arouse suspicion. Instead, he invested modest amounts in stocks and shares, and bought a static caravan in Skegness where he holidayed with his wife and grandchildren.
Barry Elener, on the other hand, regularly splashed out on foreign holidays, taking his family and friends to the Canary Islands, Spain, Portugal and Florida. He gambled away huge sums on the Lottery and the dogs, and he drank heavily. It was this that would eventually lead to his downfall.
A former licensee of the Oddfellows Arms in Shelley, Huddersfield, Barry Elener became manager of the Old King's Head pub in Allerton, where his sister and brother-in-law, Diane and Christopher Craven, were licensees.
Unable to keep details of his father's criminal exploits to himself, he bragged to customers about robberies and laundering dye-stained banknotes.
Police making routine inquiries about a possible sighting of the getaway car used in the Tasawar Hussain murder chanced upon a man named Gerald Short. It was then that the vital breakthrough came.
Mr Short recalled conversations with Barry Elener in the Old King's Head, when Elener had admitted carrying out armed robberies. While doing decorating work in the pub kitchen, Mr Short had spotted bundles of stained £10 notes, from which Elener said he could not remove the dye.
Giving evidence in the trial, Mr Short said Barry Elener had told him that he and his father had got away with a number of robberies, most recently at the Co-operative store in Otley Road, Bradford.This was one of only two robberies he was actually found guilty of.
Barry Elener told Mr Short he had given his brother-in-law £5,000 in stained £10 notes from the Co-op robbery and was paying him £3 for every £10 to get the dye out.
Det Supt Allan Doherty, who led the inquiry, said: "As soon as we established that Derek Elener was a former Securicor employee, we were fairly sure he was our man.
"The Eleners were desperate, dangerous men and we couldn't risk their injuring another member of the public, or worse. We placed the pair under surveillance for a short time and then carried out firearms raids on their houses."
There, the police found cash that tied the Eleners to the robberies at Madina Travel, in Bradford, after which Tasawar Hussain was murdered, and the Otley Road Co-op, stained with distinctive red security dye. The evidence was so overwhelming that Derek Elener pleaded guilty to murder and 27 other charges, including 12 robberies, before the case came to trial.
A red VW Jetta car parked in Jowett Street, where Mr Hussain was gunned down, was also found to belong to the Eleners.
When the pair slowed to a standstill in their Nissan Sunny getaway car, they were intending to make their escape in the Jetta. Mr Hussain got in the way of those plans and paid with his life.
The murder weapon has never been recovered, but it has not been used in any robbery since the Eleners' arrests.
Det Supt Doherty said: "We identified a total of 28 robberies which we believe were part of this same series and Derek Elener has since indicated a number of incidents he has not been charged with. Our inquiries will continue."

sally.cope@ypn.co.uk