Sheku Bayoh’s partner Collette Bell will address a conference in Glasgow as the family’s campaign for justice is officially launched.
Collette will join Sheku’s brother-in-law Ade Johnson and the family’s lawyer Aamer Anwar to speak at the event being jointly hosted by Scotland Against Criminalising Communities.
The conference will examine wider issues surrounding deaths in police custody and will also hear from relatives of others who have died in custody.
They include Janet Alder and Marcia Rigg, the sisters of Christopher Alder and Sean Rigg.
Sheku’s death in police custody in Kirkcaldy on May 3 is still being probed by the Police Investigations and Review Commissioner.
The 31-year-old lost consciousness after he was restrained by police officers who used CS spray, PAVA spray and batons.
Collette, the mother of the youngest of Sheku’s two sons, and his family are fighting for the truth of what happened on the morning of the gas engineer’s death.
Mr Anwar said the event on July 25 would allow the family to learn from other high-profile cases as well as officially launching their own campaign for justice, which he warned could take years to get to the truth.
He said: “The family realise they are in for the long haul.
“They are aware of the fact it will be several months before they get any semblance of answers.”
He added: “As for the truth that is a long way away.
“They have said time and time again they have faith in the Lord Advocate and the PIRC but that faith is not blind.
“They are not willing to sit and wait for one year or two years then find out different procedures should have been adopted in the beginning.
“With something like this, you can expect it to take several months, a year, and possibly years before you get to the truth of the matter. Certainly that’s been the experience of many of the families who will be speaking on the 25th.”
Musician and music producer Sean Rigg, 40, died at the entrance to Brixton Police Station in 2008.
Former paratrooper Christopher Alder died in police custody at Queens Gardens Police Station, Kingston upon Hull, in 1998.
The conference will be held in the Renfield Centre.