A sergeant and two detention officers have been cleared over the custody death of Thomas Orchard - who died a week after a struggle at a police station.
Mr Orchard, 32, a paranoid schizophrenic, was arrested on suspicion of a public order offence on an Exeter street in October 2012.
While being restrained at Heavitree Road Police Station Mr Orchard suffered brain damage and a cardiac arrest. He died a week later.
During a retrial at Bristol Crown Court, the jury heard how Mr Orchard was restrained by his hands and feet, and an emergency response belt placed over his face.
On Tuesday, custody sergeant Jan Kingshott and detention unit staff Michael Marsden and Simon Tansley were cleared of manslaughter by gross negligence following hours of deliberation.
During the 10-week trial, the court heard how Mr Kingshott, 44, Mr Tansley, 38, and Mr Marsden, 55, were all involved in the restraining of Mr Orchard.
All three men were described as men of honesty and integrity during their trial.
None of them had had any kind of disciplinary proceedings brought against them during their time at Devon and Cornwall Police.
He had not taken his medication for seven days and told a mental health professional he believed he was a vampire and should stay inside during the day of his arrest.
Initially he was dealt with by seven police officers before being transported to Heavitree Road.
Mr Orchard, who was 5ft 7in, was then carried to a cell by four officers, placed chest-down on a mattress and searched while handcuffed and in restraints, with the ERB around his face.
Twelve minutes later officers returned to his cell where they found him unresponsive, after which he was taken to hospital.
According to prosecutors, a combination of force and physical restraints, coupled with a "complete failure" to realise Mr Orchard's condition and observe him closely, led to his brain being starved of oxygen and caused him to suffer a cardiac arrest.
Following the verdicts, Mr Orchard's parents, Ken and Alison, described the outcome as a "setback".
"Today we join a growing group of people who have lost loved ones in police custody and have found no sense of justice", they said outside of court.
"Thomas cannot be brought back but we want his needless death to bring about change.
"And the change we want most is in the attitude of the police, particularly towards those with mental health vulnerabilities".
Mrs Orchard described her son as a "country-loving, nature-loving, free child" who had found school difficult, in part due to hearing problems.
"He struggled in a number of different ways but he was a dear, dear boy," she said.
"He was very sensitive. He was absolutely at home in trees or in the garden", Mrs Orchard added.
Sarah Green, deputy chairwoman of the Independent Police Complaints Commission (IPCC), said that subsequent disciplinary proceedings were "currently under consideration" for the staff involved in the restraint.
A spokesman added: "The IPCC continues to examine Devon and Cornwall Police's corporate decision-making around the ERB.
"Investigators are conducting detailed analysis to fully understand the force's policies and processes governing its use."
Chief Constable Shaun Sawyer said: "I fully recognise the impact of these long-running and difficult proceedings upon the family of Mr Thomas Orchard, his loved ones and friends, with whom my thoughts and condolences remain."