THE death certificate of man who died after being restrained by up to nine police has confirmed the presence of ecstasy and a legal high in his blood stream.

A register of Sheku Bayoh's death has now supported rumours that he had been under the influence of drugs when he died last May in police custody.

It shows he had consumed two substances, ecstasy and a former legal high know as flakka.

The updated description of his cause of death - previously listed as being "unascertained (pending investigation)" - has been described as a "significant development".

But lawyers acting for Mr Bayoh's family said there was nothing significant about the toxicology report and that police officers are trained to deal with "vulnerable individuals" and that any force used "must always be legitimate and proportionate".

Sheku Bayoh, 31, died following an incident to which officers were called alleging a man had been seen in the streets of Kirkcaldy, Fife, around 7am on Sunday, May 3, 2015 carrying a knife.

Mr Bayoh did not have a blade during his arrest that saw one female officer injured but one was later found nearby.

The father-of-two, described in the certificate as a gas suppliers' contact centre customer service advisor, was recorded as having died at 9.04am at Victoria Hospital in Kirkcaldy.

He was originally from Sierra Leone but had lived in Scotland since he was 17.

A Fatal Accident Inquiry into the circumstances surrounding his death is to be held following the Police Investigations and Review Commissioner (Pirc) probe which was concluded in August.

However, the Bayoh family solicitor Aamer Anwar has called for a wider public inquiry include investigations into the "restraint techniques, training, and use of sprays and batons" on the dead man.

Professor Peter Watson, the lawyer representing police officers involved in the incident, said the circumstances surrounding the case would be examined.

"This is a significant development and it gives a context to what the police officers had to deal with," he said.

“It is very unfortunate for both Sheku Bayoh and for the officers who had to deal with him that they were facing the circumstances that someone had taken a drug which is both mind altering and affects the consciousness, placing himself and other people at risk."

The document, signed by Mr Bayoh's sister Kadijartu Johnson, records the Sierra Leonean's late father has having been a senior government officer.

Mr Bayoh's mother Aminata Bayoh travelled from Sierra Leone last year for her son's funeral, which was also attended by Edward Turay, Sierra Leonean High Commissioner to the UK.

The certificate states under cause of death: "Sudden death in a man intoxicated by methylenedioxymethamphetamine (ecstasy) and alpha - pyrrolidinopentiophenone whilst being restrained."

The stimulant known as flakka has been described as the "zombie drug" in the US and Australia amid claims of its effects on users who overdose on the manufactured substance also sold there as bath salts.

Solicitor Aamer Anwar said: “The Lord Advocate's team continues to carry out an extremely complex investigation into the death of a young man whilst being restrained by up to nine police officers. There are many other matters which are hugely significant but ‘speculation’ and ‘cherry picking’ by those who should know better is deeply unhelpful and inappropriate.

"Sheku's family stated from the very beginning that his behaviour was out of character, but police officers are trained to deal with vulnerable individuals and any force used must always be legitimate and proportionate.'

A Crown Office spokesman said: "The PIRC report has been carefully considered. The Crown requires to undertake further work before a decision can be made as to whether or not there should be any criminal proceedings. That work is in hand.

"We will continue to liaise with the nearest relatives of the deceased's family to ensure that they are kept fully informed of the progress of the investigation"

"It would not be appropriate for the Crown to comment further at this time."