A store manager who was knifed during a suspected robbery in an east London shopping centre died of a stab wound to the neck, post-mortem tests revealed.
Jamie Simpson had worked in the store for three years
Jamie Simpson, the assistant manager of the Matalan store at Kingsland Shopping Centre in Hackney, was attacked as he was cashing up on Saturday evening.
Detectives are still examining CCTV footage obtained from the store.
Officers believe three men "lay in wait" before confronting the 33-year-old victim.
The attackers are believed to have run from the store via the rear car park in Dalston Lane.
Officers have released CCTV images of three suspects in the shopping centre.
Mr Simpson, of Herne Hill, south london, had worked at the store for the past three years.
Officers remain at the scene and the area has been cordoned off.
A statement issued by Matalan said: "Our first priority at this time is the welfare of the other members of staff at the store. Our thoughts and condolences are with the family and friends."
The CCTV image released by the police shows three suspects
On Sunday Det Insp Lawrence Smith said: "We believe that the three individuals involved lay in wait at the store and then confronted the assistant manager.
"The description that we have of them is of three young black males."
The officer added there were no witnesses to the murder.
He was found by staff shortly after the attack in an office area where he was working.
Earlier Det Insp Jackie Sebire said: "Mr Simpson was known as a reliable and diligent member of staff."
Police believe the store was targeted and extra police officers have been deployed to the area.
Officers have appealed for information on anyone in the shopping centre who was seen "acting suspiciously" in the evening or witnessed the assailants fleeing the scene through the car park.