The latest murder probe was launched last Friday after Jordan Marples-Douglas, aged 23, was stabbed in a house on Woodthorpe Road, Woodthorpe.
Two arrests have been made over the killing.
Another 10 case are still being worked on, including the death of a nine-week old baby, a two-year-old boy and a mum-of-four.
Anyone with information about any of the deaths should call South Yorkshire Police on 101 or Crimestoppers on 0800 555111.
1. Jordan Marples-Douglas
Jordan Marples-Douglas, aged 23, was stabbed to death in a house on Woodthorpe Road, Woodthorpe, Sheffield, on Friday, March 6. Two arrests have been made. Photo: JPI Media
2. Isaiah Usen-Satchell
Isaiah Usen-Satchell, 18, was stabbed to death in Norfolk Park in the early hours of New Year's Day. Arrests have been made but nobody has been charged. Photo: JPI Media
3. Kavan Brissett
Kavan Brissett, 21, was stabbed off Langsett Walk, Upperthorpe, in August 2018 and died four days later. Nobody has yet been charged over his death. Photo: JPI Media
4. Nadeem Qureshi
Nadeem Qureshi, 40, from Manchester, was found injured on waste land on Station Road, Deepcar, Sheffield, on July 24. Arrests have been made but nobody has been charged. Photo: JPI Media