Scotland's most senior police officer is set to be sued for £2 million over the death of Sheku Bayoh.

The father-of-two's family claim police officers were responsible for his death and are finalising a legal case against Police Scotland's Acting Chief Constable Iain Livingstone.

The civil action, which will be lodged at the Court of Session in Edinburgh this week, will mark the first time police in Scotland have been sued over an alleged unlawful killing.

Mr Bayoh, 31, died after being restrained by officers in the street near his home in Kirkcaldy, Fife, on May 3, 2015.

He was found with more than 20 facial cuts and bruises, signs of asphyxiation, a fractured rib and grazing on his chest.

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.

Speaking to the Sunday Mail, a source close to the Bayoh family said: “A case for damages will be lodged ahead of the third anniversary of Sheku’s death.

"The family have had not a penny for legal costs or anything else and feel the case is just dragging on and on.

“They miss Sheku every day and remain utterly distraught at his death and the manner in which he died. No sum of money will bring him back. Three years on, there’s still no conclusion to an investigation.”

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

Ms Bell said: "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.

“The Crown keep saying it’s a complex investigation but I’m sick of excuses. If it was nine ordinary people who’d done this, I doubt the Lord Advocate would have taken three years to make up his mind.

"I will not rest until I have answers for myself, my son and the people of Scotland.”

A Crown Office spokesman said: “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.

“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.”

Police Scotland Assistant Chief Constable Wayne Mawson said the force was committed to cooperating with the PIRC and the Crown Office.