A man who died after stealing and crashing a private ambulance was being treated for mental health problems, the BBC understands.
Michael South, 40, hit a double-decker bus on the A64 near York, on Friday.
He was being transported between hospitals when the ambulance, owned by ERS Medical, was stolen.
Leeds and York Partnership NHS Foundation Trust, which is understood to have been treating Mr South, said it would not comment.
Ben Aked, a friend of Mr South, said he should have received greater care after claims he had tried to kill himself on a previous occasion.
Mr Aked said: "He did need help and the fact he cried out for help for so long and no one had helped him."
Bus driver injured
North Yorkshire Police said the vehicle had been reported stolen at around 20:10 BST on Friday.
Mr South was the only person in the vehicle at the time of the crash and was pronounced dead at the scene.
The bus driver suffered serious leg injuries and was taken to hospital where his condition is described as stable. Five other passengers received minor injuries.
A spokesman for ERS Medical said: "We can confirm that one of our vehicles was involved in an incident on the A64 on Friday, April 10.
"We are working closely with all the agencies and helping them with their ongoing enquiries."
A spokeswoman for the Care Quality Commission, the independent regulator of health and social care services in England, said: "The CQC is liaising with the relevant authorities to determine whether action on our part is required."