Investigators have handed two files to the Crown Prosecution Service after separate probes into the death of a Birmingham dad.
Four police officers have previously been arrested and bailed on suspicion of the manslaughter of Kingsley Burrell, who died in custody two years ago.
A file by the Independent Police Complaints Commission relating to those officers has now been passed to the CPS, which will now decide if anyone is to face charges.
Meanwhile, a second file compiled by Dorset Police about the actions of non-police medical staff has also been submitted to the court prosecutors.
Trainee security guard Mr Burrell, aged 29 and from Hockley, called police on March 27, 2011, claiming to have been threatened by a gang.
Officers who arrived at the scene in Ladywood detained the dad-of-two under the Mental Health Act. Within hours, he was sectioned and taken to a mental health unit in the city.
Three days later police were called to the Mary Seacole mental institute in Winson Green after an “incident” and Mr Burrell was transferred to the Queen Elizabeth Hospital, where he died on March 31.
A spokeswoman for the Independent Police Complaints Commission said: “The IPCC has completed its investigation into the death of Kingsley Burrell and a file of evidence was submitted to the Crown Prosecution Service.
“Four police officers were involved in the transportation of Mr Burrell from one mental health facility to another and had placed Mr Burrell while under restraint into a seclusion room at a mental health unit in Birmingham.
“Dorset Police, which has carried out a separate investigation at the request of the IPCC into the actions of non-police medical staff, has also submitted a file of evidence to the CPS.
Four West Midlands police officers have previously been arrested and interviewed by the IPCC under criminal caution. A number of other police officers have been interviewed as witnesses during the course of the investigation.”
Mr Burrell’s funeral took place in Handsworth last August, 17 months after his death.
Family and friends have held a number of protest marches demanding answers about how he died .
West Midlands Police said the four serving officers had not been suspended.