A "meticulous" and "very careful" police analyst could not explain how he failed to see a 91-year-old woman with a walking frame in the road as his vehicle fatally collided with her, a court has heard.
Stuart Bodgers walked free from court after a judge was told the incident preyed on the mind of the Greater Manchester Police civilian employee "every day" and he had been diagnosed with post-traumatic stress disorder.
"Sprightly" former dinner lady Joan Pimblett died in hospital a few days after the collision in Heaton Moor Road, Stockport, on the morning of January 27 last year.
Bodgers, 52, was arrested and interviewed but could not account for how he did not see Mrs Pimblett until it was too late to avoid impact.
Two motorists, one travelling behind Bodgers, clearly saw the great-grandmother crossing the road and slowed down, Manchester Minshull Street Crown Court heard.
The subsequent collision investigation found Bodgers was travelling at up to 20mph in a 30mph zone in his Nissan Navara, was not using his mobile phone, was not distracted by any instruments in the car and was not under the influence of drink or drugs.
Judge Paul Lawton said the two motorists were "aghast" there was no reaction to the pensioner’s presence and added: "It is more than a momentary lapse, it seems to be a sustained lapse in concentration."
The judge said he was at a "complete loss" to explain the loss of concentration, as were the police and the Crown Prosecution Service.
Mark Rhind, defending, said Bodgers too was "struggling to explain how this happened".
Mr Rhind said: "His character references show he is a solid, very careful, very methodical, hard-working, law-abiding, decent man of positive good character.
"He had a clean driving licence and no previous convictions. Not in any sense a reckless person.
"He does a useful job. It is clear he is meticulous. He works for the police as an analyst, doing a job in public service.
"This has been an incident which has had a massive and profound effect on Stuart Bodgers and his life. It preys upon his mind every day."
A victim impact statement from Mrs Pimblett’s son Colin, who was in court with his two brothers, said the events had had a "deep and lasting effect".
Judge Lawton said the fact that Mrs Pimblett was a "sprightly lady living an independent life" at her age made her loss even more tragic for her family, but he said it would be "branded on the consciousness" of the defendant for the rest of his life.
He sentenced Bodgers, a man of "hitherto impeccable character", to eight months in jail, suspended for two years, and ordered him to perform 100 hours of unpaid work for the community.
The defendant, from Boundary Road, Cheadle, who pleaded guilty at an earlier hearing to causing death by careless driving, was also banned from driving for two years.
Following her death, the family of Liverpool-born Mrs Pimblett said: "She was an independent and active pensioner with many friends and was frequently seen in the local shops, cafes and restaurants.
"Despite her age, she continued to travel, having family both in the UK and across the globe.
"She will be sadly missed by both family and friends, tragically taken before her time."