A man stabbed to death during riots on Saturday in Birmingham was murdered by a gang of up to 11 men.
The rioting involved youths from the black and Asian communities and was said to have been sparked by a claim that a girl of 14 had been raped.
Isiah Young-Sam was yards from his home when he was attacked - police said the ethnicity of the attackers and their motive were "unclear".
Another man was shot dead on Sunday near the scene of further disturbances.
Two men have been arrested over the shooting in the Newtown area but police do not yet know if it is linked to the weekend violence.
The Independent Police Complaints Commission (IPCC) said it was investigating the response by West Midlands Police but that no police firearm was discharged during the evening.
Thirty two people remain in hospital after the disturbances in Lozells on Saturday evening.
Detectives said that forensic experts had been to the location of the alleged attack on the girl in the Lozells area but no formal complaint had been received.
Speaking at a press conference on Monday Det Supt David Mirfield said Mr Young-Sam, his brother and two friends had been to watch a film at a cinema on Broad Street in Birmingham city centre before catching a bus and walking the short distance home along Carlyle Road.
"Three cars pulled up with between 10 and 11 men inside."
"The men got out of the cars armed with knives and attacked Isiah and his friends."
Mr Young-Sam, 23 an IT analyst at Birmingham City Council, died from a single stab wound to the chest. One of his friends was also stabbed in the back.
Police said he was an innocent victim and not involved in the rioting.
Det Supt Mirfield said it appeared the attackers had made attempts to disguise their appearance.
He said: "I don't want to speculate on what colour they may have been or the nature of their ethnicity.
"Isiah was walking along the road with his brother when he was attacked by these people. The motive for the attack is unclear."
He appealed to witnesses to come forward and any CCTV or phone pictures which might be relevant to be handed over to police.
Glyn Evans, director of business solutions and IT at the council, said Mr Young-Sam joined as a trainee five years ago and would be sadly missed.
He said: "Isiah was a very pleasant and hard working young man.
"He was very popular with his colleagues and had a bright future in front of him.
"He will be greatly missed. I and all his colleagues extend our deepest sympathies to his family and friends."
Heavy police presence
A number of meetings have taken place in recent days in Lozells in protest at a lack of action over the reported rape.
The rape claim was also said to have been broadcast on a pirate radio station and put out on a community-based website.
On Sunday night further disturbances took place in the Lozells area, where a heavy police presence was in place.
Gangs of youths had gathered in response to an alleged attack on a nearby mosque.
Police said they were dispersed by a series of operations between 2200 and 0100 BST and the heavy rain across the West Midlands also helped to break up the crowds of youths.
Hours later police were called to Melbourne Avenue, about a mile from Lozells, in response to reports that a man had been seen with a firearm in the area.
A number of petrol bombs were also thrown and at least 12 gunshots were reported.