Kavan was stabbed once in the chest near Langsett Walk, Upperthorpe, on Tuesday, August, 14 and died four days later in hospital.
Ahmed Farrah, aged 29, who is also known as Reggie, is wanted in connection to the murder and police have so far failed to locate him.
They today issued a re-appeal in a bid to track him down.
Detective Chief Inspector Jude Ashmore, the senior investigating officer, said: “Efforts to find and arrest Farrah, who is known to frequent the Broomhall area of Sheffield, have been ongoing but so far we haven’t been able to locate him.
“I’d now like to ask for your help – if you know where he is, or have seen or spoken to him recently, then please contact us. If you do see him, do not approach him but instead call 999 straight away.
“I’d also like to remind anyone who is letting Farrah stay with them, or helping him to evade arrest by any means, that you are committing a criminal offence which could result in prosecution.
“Farrah knows he is wanted and is deliberately avoiding police and I’d ask anyone who has any information, and Farrah himself, to think about Kavan’s family and the pain they are suffering. Do the right thing and contact police.”
If you see Farrah, please call 999. If you have any other information as to where he might be, please call either 101 or the incident room to speak to detectives directly on 01709 443507.
You can also speak to Crimestoppers on 0800 555111. Please quote incident number 827 of 14 August 2018 when passing on information.