Roberts was known to be civil and polite when sober, but bad-tempered and violent when drunk, having developed a taste for alcohol while working at a brewery in Islip. He later moving to Witney where he became the lodger of Mrs Hester Merrick of Meeting House Lane (now Marlborough Lane).

It was here that Roberts met and apparently fell for his landlady's daughter Ann. Ann turned down his advances, but Roberts persisted in his efforts to win her over. Their close proximity, as well as Ann's repeated rejection of Roberts' advances, quickly caused conflict in the household. Following a squabble, Ann began to avoid Roberts as much as possible, adding to Roberts' resentment.

On the evening of Saturday 29 July 1871 Roberts returned to his lodgings heavily intoxicated and kept the household awake until after midnight with his drunken revelling.

The following morning a clearly quite hungover Roberts was observed by his landlady drinking a cup of tea with another lodger John Godfrey. Godfrey reported that Ann was on her hands and knees cleaning the floor at the time.

Roberts went briefly outside and returned carrying an axe. Then without any warning, he raised the axe with both hands and struck Ann twice about the head. He then dropped the axe and calmly walked out into the lane.

John Godfrey followed him, crying "What have you been doing?" to which Roberts replied, "She served me bad and I hope she's dead."

When asked where he was going, Roberts said "Up there" and set off down the street towards the police station. On the way, Roberts and Godfrey met a police constable named Cope who, on being told what had taken place, locked Roberts in a police cell and returned to survey the scene of the crime.

Ann Merrick was grievously injured, eventually dying four weeks later on 25 August. As a result, the charges against Roberts were upgraded from 'grievous bodily harm' to 'murder'.

At his trial at the Oxfordshire Assizes the following March Edward Roberts pleaded 'not guilty', but it only took the jury 3 minutes to return a verdict of 'guilty', and for the judge to pass a sentence of death.

Edward Roberts hanging a few days later is notable in the annals of Oxfordshire crime for being the first execution carried out in private after the passing of the Capital Punishment Amendment Act in 1868, which banned public executions in the United Kingdom.