Police have classified the seemingly random killing of Indian student Anuj Bidve on a Salford street as a hate crime.
Bidve, 23, was walking towards Manchester city centre with a group of eight friends in the early hours of Boxing Day when they were approached by a man who crossed the road towards them.
The man approached Bidve and is thought to have asked him the time before pulling a gun and shooting him in the head at point-blank range. He then fled with a companion.
Five people have been arrested.
A 20-year-old suspect joined a 19-year-old, a 17-year-old and two 16-year-olds in police custody for questioning.
"We've not yet established a motive for this murder and there is no evidence or information at this time to suggest it's racially motivated. However, because of concerns and perceptions in the community we are going to be treating this as a hate crime," said Chief Supt Kevin Mulligan.
"We will leave no stone unturned to find the person responsible."
He said Greater Manchester Police was working closely with the Indian High Commission to get members of Bidve's family to Britain as soon as possible.
He stressed the importance of finding the murder weapon and appealed for witnesses.
Bidve, who was studying microelectronics at Lancaster University, was going to Manchester in the hope of getting a spot at the front of the queue for the Boxing Day sales.
Hundreds of people have signed up to take part in a candlelit peace march from the India Gate to the British Embassy in New Delhi to honour him.
Anyone with information on the case can contact Greater Manchester Police on 0161 856 5448.