Toowoomba man Robert Brown has been remembered for his "infectious smile" after the 75-year-old died from injuries suffered during an alleged violent robbery.
Four teenagers have been charged over the alleged assault and police said charges were expected to be upgraded following a post-mortem report.
An 18-year-old man and 16-year-old boy were arrested on Monday night and charged, and they have since faced court.
On Wednesday, police arrested another 16-year-old and a 17-year-old at a Drayton address and later charged them with multiple offences.
Mr Brown was waiting at a Margaret Street taxi rank on Monday evening when he was allegedly pushed from behind.
Police said the 75-year-old had been "minding his own business" when he was allegedly shoved to the ground and suffered serious injuries.
It is alleged Mr Brown's backpack was then stolen.
The Queensland Police Service said Mr Brown died today after he succumbed to his critical injuries.
Unique photographer
The Toowoomba Photographic Society has paid tribute to Mr Brown, who was a life member.
"Robert [was] a unique storytelling photographer who captured many events and notable happenings around the region," the society's Tryg Helander said.
He said Mr Brown was particularly fond of photographing the shopping centre where he was attacked.
"Of note was his many prints of the growth of Grand Central, his happy hunting ground, ironically," Mr Helander said.
"Robert had an infectious smile that you could feel in your heart; his enthusiasm for photography too was inspiring.
"We collectively miss your humble nature, your creativity, and that wonderful smile."
Police are still calling for anyone who has found his backpack or has dashcam footage to come forward.
Investigations are continuing.
