Photographed left to right, top to bottom is Demi Dunford, Alex Taff, Osai Williams and Andrew Horton (Source: South Yorkshire Police)
Four people involved in an organised drug supply operation across Sheffield have been convicted of murder following the fatal shooting of a 26 year old man during a dispute over drugs.
After a six week trial at Sheffield Crown Court, a jury on Monday, 16 December, found Demi Dunford, Alex Taff, Andrew Horton and Osai Williams guilty of the murder of Abdullah Hassan, who was shot dead in April 2023.
Emergency services were called to flats on Callow Drive on 9 April after residents raised the alarm. Paramedics and police attempted to save Mr Hassan’s life, but he was pronounced dead at the scene. A post mortem examination later confirmed he died from a single gunshot wound to the thigh.
An investigation by South Yorkshire Police established that the shooting followed weeks of tension between Mr Hassan and Dunford, linked to drug supply and dealing in the area. Prosecutors told the court that Dunford, seeking to assert her position within the drug network, planned the attack with the assistance of Taff, Horton and Williams.
On 8 April, the group lured Mr Hassan out of his flat on Callow Drive. As he exited through a fire door, he was shot in the upper thigh. The group then fled the scene.
In the days following the killing, the defendants attempted to conceal their involvement. Dunford and Williams travelled from Sheffield to London and later to Southend on Sea, staying overnight before returning to Sheffield, where Dunford was subsequently arrested.
Two days after the shooting, Horton, accompanied by his sister Emma Horton, took a car used to drive Dunford and Williams away from the scene to a car wash in the Attercliffe area of the city in an attempt to remove forensic evidence. Investigators later recovered mobile phone data that led to Emma Horton being charged with conspiracy to pervert the course of justice.
Evidence presented during the trial included CCTV footage, forensic findings, mobile phone analysis and ballistic reports, which prosecutors said clearly linked the defendants to the planning and execution of the attack.
The jury returned the following verdicts:
- Demi Dunford, 29, of Derby Street, Sheffield, was found guilty of murder and two counts of possession of controlled drugs with intent to supply.
- Alex Taff, 31, of Springfields, Rotherham, was found guilty of murder.
- Andrew Horton, 48, of HMP Doncaster, was found guilty of murder and conspiracy to pervert the course of justice.
- Osai Williams, 29, of HMP Lowdham Grange, was found guilty of murder.
- Emma Horton, 38, of Blackstock Road, Sheffield, was found guilty of conspiracy to pervert the course of justice.
Speaking after the verdicts, Senior Investigating Officer Detective Chief Inspector Andy Knowles said justice had been secured following a lengthy and complex investigation.
He said drug related disputes frequently escalate into serious violence, adding that the case highlighted the wider danger posed by the links between firearms and organised drug crime.
“These crimes do not only affect those involved,” he said. “They create dangerous situations where innocent people can be placed at risk, spreading fear and instability across communities.”
Dunford, Taff, Horton and Williams are due to be sentenced at Sheffield Crown Court on 16 January 2026.
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