The family of a man who died under psychiatric care have called for "justice" and "answers".
Jonathan Malia sought help for bipolar disorder and was transferred to a private secure unit.
The 24-year-old father, of Handsworth, Birmingham, was treated in the city but was then moved to Hertfordshire. It is thought he died from a heart attack caused by a blood clot.
The hospital in Stevenage where he was being treated said it did all it could.
A second post mortem examination took place on Monday and an inquest is due to follow.
Errol Robinson, the family's solicitor, said they wanted to establish whether being sedated was a contributing factor.
He said: "This young man was admitted to psychiatric care, was compulsorily detained, was given, as we understand it, anti-psychotic medication and then ends up, a short time later, dead."
Mr Malia was admitted as a voluntary patient at the Queen Elizabeth Hospital in Selly Oak on 4 January before first being transferred to Meadow Croft Hospital in Winson Green and then to the Cygnet Hospital in Stevenage, Hertfordshire.
He was taken to Lister Hospital in Stevenage after reportedly collapsing and he died on 17 January.
His aunt Michelle Fullerton said: "We couldn't understand why he wasn't allowed to have any visitors, why nobody was allowed to go there to him.
"And he wasn't allowed to make any phone calls so he was basically left on his own really with no one to advocate for him.
"We want justice. We need answers, we've got loads of questions that are not answered and we feel like we're up against a brick wall."
One of his younger brothers, Joshua Malia, said: "I'm still looking for answers.
"He was a healthy lad and it was a shock getting the phone call that he'd passed away."
Mr Malia's mother also has bipolar disorder and has been receiving treatment in hospital since his death.
A spokesperson for Cygnet Hospital offered condolences and said: "Nothing is more important to us than the wellbeing of those who use our services.
"Whilst we await the final reports, we believe that we did all that we could to look after Mr Malia whilst he was at our facility."
An inquest is due to take place and the hospital said it would "work closely" with the family and authorities.