An Aboriginal man has died in custody after his “condition deteriorated” in a regional Victoria police station last week.

Police said the man, aged 30, was arrested on Thursday in Horsham, about 300km northwest of Melbourne, for allegedly breaching a court order.

He was taken to Horsham police station where, police said, his “condition deteriorated”.

In a statement, Victoria Police said the man was taken to hospital via ambulance that afternoon and died in hospital on Sunday.

“The homicide squad will investigate the death, with oversight from professional standards command,” the statement said. “This is standard protocol when a person has died in police custody.”

It comes as Aboriginal people in Victoria are awaiting the outcome of an inquest into the death in custody of Yorta Yorta woman Tanya Day, who died in hospital in December 2017, more than two weeks after sustaining a fatal brain injury from falling in the cells of Castlemaine police station.

Day’s family have called for an investigation into possible criminal negligence by police.