A picture emerging of events before Sheku Bayoh’s death suggests that the 31-year-old was on the ground and subdued within 40 seconds of police arriving.
Police Scotland is under investigation over the circumstances surrounding the death of the father-of-two in custody.
Mr Bayoh, of Kirkcaldy, was held and put in leg restraints shortly before he died in Victoria Hospital on the morning of May 3.
His family and partner Collette Bell, 27, are fighting for the truth of what happened, claiming police gave several different accounts.
Collette, mother of Mr Bayoh’s four-month-old son Isaac, said: “What I am learning about the way Sheku was treated in his final hour has shocked and disgusted me.
“We must fight this case so no other family has to go through this horrible, hurtful ordeal.”
Witness statements have been collected by the Police Investigations and Review Commissioner (PIRC) in an inquiry into the incident in Hayfield Road.
The actions of nine uniformed police officers and two CID are being examined.
According to a report in the Sunday Mail, it is understood that two male officers arrived in the first police van, followed by a second van with a female and male officer.
A source said the officers surrounded Mr Bayoh and it is claimed the woman, who was closest, was punched and fell to the ground.
It was also claimed that Sheku was then on the ground, CS spray was used and several officers were on top of him.
At least five of the nine uniformed officers were involved in restraining him by the knees and ankles, it was stated.
The Scottish Police Federation previously claimed the female officer responded a call of a man brandishing a knife, and feared for her life.
A post mortem was inconclusive and the results of further tests are awaited as the PIRC investigation continues.
Meanwhile, a new venue has been found for a fundraiser on Sunday arranged by Mr Bayoh’s family.
It was initially to be held at Fifty High Street, Kirkcaldy, but cancelled amid allegations of police pressure, which the venue denied.
The fun day will be held at the town’s Windsor Hotel.