THE family of a father-of two who died in police custody are to launch an "unprecedented" legal case against Police Scotland's Acting Chief Constable Iain Livingstone.

Lawyers acting for the relatives of Sheku Bayoh say they intend to take action in the civil court, three years after his death in 2015.

It is believed the case is the first time the police have been sued over an alleged unlawful killing in Scotland.

The announcement comes on the third anniversary of Mr Bayoh's death, with the family still awaiting to hear if any of the officers involved will face criminal charges.

Deborah Coles, director of the charity Inquest - which supports the families of those who suffered a state-related death - is will also raise the case with Tendayi Achiume, the United Nation's Special Rapporteur on racism.

Mr Bayoh, died after being restrained by officers in the street near his home in Kirkcaldy, Fife, on May 3, 2015.

The 31-year-old, who was originally from Sierra Leone was found with more than a dozen cuts and bruises, signs of asphyxiation, a fractured rib and grazing on his chest.

READ MORE: Sheku Bayoh 'fought with Mikaeel Kular’s father' in Kirkcaldy before police called

The Police Investigations and Review Commissioner (PIRC) filed a report on his death to prosecutors in August 2016.

However, the Crown Office has yet to decide what, if any, charges will be brought.

Aamer Anwar, the lawyer for Mr Bayoh's family, said: “On May 3rd it will be the three years since Sheku Bayoh was restrained by up to nine police officers and lost his life.

"Since then Sheku’s loved ones have waited for clarity as to the circumstances in which their beloved son, brother and partner died.

"Despite the passage of time, their pain remains raw and their grief made worse by the failure of the authorities to provide them with the answers they are entitled to."

Mr Anwar said that the family  had decided that "enough is enough", and that that Police Scotland’s officers failed in their duty of reasonable care to protect the life of Sheku Bayoh.

READ MORE: Family of Sheku Bayoh launch campaign calling for answers over his death in police custody

He added: "No amount of money will bring Sheku Bayoh back – this, for the family, is about justice.”

Mr Bayoh's family and his partner Collette Bell, mother of his son Isaac, have previously criticised the length of time the investigation has taken.

Ms Bell told the Sunday Mail: "Three years later, I’m still awaiting answers for our son. Isaac has said his first words, taken his first steps, celebrated birthdays and started nursery – and all without his father at his side.

“All I’ve ever wanted is to know the truth surrounding Sheik’s death so I can one day explain to my son why he is growing up without his daddy."

READ MORE: Sheku Bayoh: Campaign for justice launched over his death in police custody

A Crown Office spokeswoman said:“We recognise that this has been a difficult time for the family of Sheku Bayoh. The family, and their legal representative, have been kept informed of any significant developments and senior Crown Counsel along with Crown Office officials met recently with the family and will continue to do so where appropriate.

“This has been a complex and challenging investigation and while there is still some further work to do, considerable progress has been made in the last few months. 

"It is not appropriate at this stage to commit to any timescales given the nature of the investigation, however, it’s anticipated a full report will be submitted for the consideration of Crown Counsel, the most senior lawyers in the Crown Office, in due course.”