VIDEO: 'Think long and hard about what you know' - Detective's message four weeks on from broad daylight stabbing in Sheffield

Speaking at a press conference Det Chief Insp Steve Handley said he believed people still had information about the murder of Jarvin Blake which they had not reported to police.

Jarvin, 22, was stabbed at the junction of Catherine Street and Brackley Street, Burngreave, at around 3.15pm on Thursday, March 8 and four arrests have been make but nobody has yet been charged over the killing.

Det Chief Insp Handley said: "The investigation, which has progressed at pace, has meant that we have arrested four people. Sometimes members of the community when they hear that think that we have solved the case at point of arrest.

"Those people are on police bail and rightly so while we formulate further lines of enquiry and gather and develop that case. Within that we don't want people to think that the police's job is done on arrest.

"We are seeking as much information as possible about those responsible for this death, the vehicle that was used - the light blue Volvo - where the murder weapon is and whether there is any other significant evidence to help find those responsible.

"All that information is potentially out there in the community and we would like people to think long and hard about the information that they know and contact incident room or if they feel in contacting Crimestoppers, anonymously, in order to give us the information so that we can gather and secure the evidence."

Jarvin's fiancée Kelsey Dixon also spoke about the incident for the first time and pleaded for any witnesses to come forward.

The couple were due to get married in the next couple of years.

Det Chief Handley said: "This family had got a life together that there were just starting and instead of planning that life, they are planning the funeral."

Detectives released CCTV footage of Jarvin, from Gleadless, in a shop in Handsworth just hours before he was chased and knifed by the gang in the attack.

"Nothing has specifically come of it yet but it's about people being able to see that's a picture of him on the day, earlier on from the when the attack took place but dressed in the same clothing but just carrying out day-to-day activities," Det Chief Insp Handley added.

"From there we know he went to the Pitsmoor/Burngreave area and he drove there in his vehicle with another male. That other male was also the victim of an assault but to a lesser degree."

Det Chief Insp Handley said Jarvin was driving a black Vauxhall Corsa on the day of the attack, which was parked up near the scene of the attack and police have since recovered.

He added that he felt that some people may have 'allegiances' to the offenders and asked them to come forward to help police build a case for the prosecution.

Officers and detectives will be out in Pitsmoor and Burgreave tomorrow (Thursday) to gather information and raise awareness.

Anyone with any information is asked to call the incident room on 01709 443528, or Crimestoppers, anonymously, on 0800 555 111.