Most wanted: Six men with links to Sheffield urgently wanted by police over murders

Among the cases detectives are keen to crack is the murder of Kavan Brissett, aged 21, who was killed in a knife attack in Upperthorpe in August 2018.

Although South Yorkshire Police named and issued a photograph of a man believed to hold vital information about the killing, Ahmed Farrah has never been traced.

A £5,000 reward was offered by Crimestoppers but that also failed to lead police to the 32-year-old, who is also known as Reggie.

Farrah was captured on CCTV cameras at the Royal Hallamshire Hospital on the same night that Kavan was stabbed.

He returned to hospital the following day but then went to ground.

Farrah was treated for facial injuries believed to have been sustained in the same incident in which Kavan was stabbed.

He was seen in Cardiff after he went on the run, but no information on any possible sightings elsewhere has been released.

Abdi Ali is another Sheffield man wanted for questioning over a murder.

He has been named as a prime suspect in the murder of 47-year-old Shaun Lyall, who was attacked in his home in Cleethorpes in July, 2018.

Ali was born in Somali but moved to Sheffield as a child and has connections to Pitsmoor and Shirecliffe. He moved to the east coast in 2018

Craig Whittle, 46, of Corporation Road, Grimsby, was jailed for life over the murder but jurors in his trial were told that he did not act alone and Sheffield man Ali was also involved.

Ali, in his 30s, is also known as Mohammed Ismail, Black Johnny, Gulaid and Madman.

Mr Lyall was battered with weapons including golf clubs, screwdrivers, a knife, scissors and a length of wood.

The motive for the attack is said to have been missing drugs and cash that Mr Lyall was supposed to have been looking after.

Despite repeated appeals for Ali to come forward to assist police with their enquiries, he continues to evade arrest.

Anyone with information should call South Yorkshire Police on 101 or Crimestoppers on 0800 555111.