The family of a 23-year-old Manchester man who was murdered in the city say he was a "much-loved" son whose death has caused "much sorrow".
Plymouth graduate David Allan worked in WHSmith in Manchester Royal Infirmary, "cheerfully serving" through the Covid-19 crisis, they said.
Mr Allan was assaulted on Wythenshawe Road on Thursday, police said.
A 30-year-old-man from the Tyldesley area is the fourth person to be arrested over his death.
A 33-year-old man who was also arrested remains in custody and a 39-year old man and 42-year-old woman, who were arrested on Thursday, have since been released under investigation.
Mr Allan was taken to hospital after the attack at 18:00 BST, but died in hospital on Friday, Greater Manchester Police said.
A keen sportsman with hopes of becoming a quantity surveyor, Mr Allan was a member of Plymouth University hockey team and had been a fencing coach for children in Birmingham, his family said in a statement.
"David was a much-loved son, whose passing has caused much sorrow amongst his friends and family," they said.
"He recently graduated from Plymouth University and had until very recently been working at WHSmith in the Royal Infirmary despite the Coronavirus outbreak, cheerfully serving key-workers, patients and visitors alike.
"He will be very much missed," they said.
Police are continuing to appeal for information.