The police watchdog has completed its report into the death of a father-of-two in police custody.
Sheku Bayoh, 31, died after being restrained by officers in Kirkcaldy, Fife, on May 3 last year.
His family has called for a health and safety prosecution against Police Scotland and believe a wider inquiry should be held into deaths in custody.
Kate Frame, the police investigations and review commissioner (PIRC) has now completed her probe into the circumstances of Mr Bayoh's death.
Ms Frame's work focused on gathering expert evidence from specialist forensic pathologists.
The full document, which follows an interim report published last summer, will be presented to lord advocate James Wolffe, who will consider the findings before deciding what action to take.
A PIRC spokesman said: "The commissioner has submitted a supplementary report to the lord advocate on her independent investigation into the circumstances surrounding the death of Sheku Bayoh and further allegations raised by the family of Sheku Bayoh and their legal representative.
"The commissioner appreciates that this has been a difficult period for the family of Mr Bayoh whilst this complex and wide ranging investigation has continued."
The spokesman said the inquiry was delayed after "additional lines of investigation" emerged.
He added: "The commissioner ensured that all of the matters raised were rigorously explored so that the lord advocate is presented with a comprehensive report in order that he can make informed decisions on further action.
"The commissioner considered it was important that the quality of the investigation was not compromised by speed.
"She will undertake any further enquiries as directed by the lord advocate."
Lawyer Aamer Anwar, speaking on behalf of the Bayoh family, said they remained "determined to fight for justice and the truth".
He said: "This investigation has taken one year and three months to complete.
"Sadly, during this period the Bayoh family's confidence in the robustness and impartiality of PIRC's investigation has been shattered.
"The Bayoh family hope that they can maintain confidence in the new lord advocate, James Wolffe QC, to ensure all necessary further enquiries are completed by Crown Office before any conclusion is reached on what happens next.
"We understand that this process is likely to take some time."
A Crown Office spokesman said: "The PIRC report will be carefully considered but this is a complex investigation and further work may be required before any decision is made as to whether or not there should be any criminal proceedings.
"The family will continue to be kept informed of any significant developments."