David "Dave" Lester was one of the two men who staged a robbery on Mike Baldwin's factory Baldwin's Casuals in January 1978. Armed with a sawn-off shotgun, Dave and his friend Tommo Jackson followed Mike and his wages clerk Ernest Bishop to the bank in their car, intending to mug them of the money they'd withdrawn to pay the staff their wages, but Dave decided that there were too many people around and thought it better to grab the money at the factory. Dave and Tommo managed to enter the factory and get to Ernie's office unchallenged, even with their gun, and began to menace Ernie out of the wages he was preparing. Mike began to wonder what was taking so long and opened the door, knocking Tommo and causing him to shoot Ernie. In the ensuing confusion, Dave grabbed the wage packets and both men escaped the factory long before the police arrived. Ernie later died in hospital from his wounds.
Dave and Tommo were apprehended by the police within days and charged with Ernie's murder. Just before the trial, Dave's mother plead with Mike, the key prosecution witness, that the shooting was an accident. According to Mrs. Lester, Dave was a good lad who'd never said a cross word to her, but Mike didn't yield. Both men were given life sentences.