Mr Brissett, who was 21, died in hospital four days after being stabbed on a pathway in Upperthorpe on the evening of August 14.
A number of arrests have been made, but South Yorkshire Police is keen to speak with Farrah, also known as ‘Reggie’, who they believe is key to their enquiries.
The Crimestoppers charity is now offering the reward of up to £5,000 for information that leads to his arrest. Dave Hunter, head of operations for Crimestoppers, said: “A 21-year-old has had his life taken away from him and his family are understandably distraught and searching for answers.”
People can call the charity anonymously to give information on 0800 555 111.