WASHINGTON (AFP) - Alfonso Bennett's sisters agreed to take him off life support after doctors at Mercy Hospital in Chicago told them there was no hope for recovery.
Turns out it wasn't their brother Alfonso Bennett who was dying in the hospital but an entirely different man, Elisha Brittman.
The Bennett and Brittman families filed a lawsuit this week against the Chicago Police Department and Mercy Hospital in Illinois' Cook County Circuit Court claiming negligence.
The bizarre mistaken identity case dates back to late April, when a naked and badly injured man was found underneath a car in Chicago and admitted to Mercy Hospital.
Alfonso Bennett's sisters were informed by police that he was the man in hospital.
Although they had some doubts about his identify, they eventually agreed to take him off life support and move him to a hospice, where he died three days later.
As they were preparing his funeral, Alfonso Bennett turned up at a friend's barbecue, his sisters said at a press conference during which the Bennett and Brittman families announced the lawsuit.
"She said, 'He's here! He's alive!" Yolanda Harvey, one of Bennett's sisters, quoted the friend as saying.
The dead man was eventually identified through fingerprints as 69-year-old Elisha Brittman.
"The bottom line is this mistaken identity situation was something we think could have easily been avoided and should have been avoided," said Cannon Lambert, the attorney for the families.
In a statement to the Chicago Tribune newspaper, the police department said it had opened an investigation.
"To say that we currently have questions is an understatement," it said.
"We have detectives looking into every aspect of this incident - from the incident response to the circumstances leading to the hospitalisation and the notification of family members."