A depressed 40-year-old was sent home from a psychiatric hospital and handed back his car keys just two hours after he was caught attempting suicide with a plastic pipe connected to his exhaust.
Hours later Bernard Duca took his own life by hanging himself in his garage, an inquest heard this week.
It had been the third attempt at suicide he had made that day, assistant deputy coroner Dr Robert Woodroffe was told.
"It was obvious to me and I am no doctor that Bernie had some sort of problem with depression," said his friend, Martin Cronin.
"I was astounded to hear he had done this, this, this and this and still ended up killing himself. I think the guy was screaming for help and no-one heard," he told the inquest.
The saga started when Mr Duca, a landscape gardener and property investor from Shenley Road, Bletchley, arrived at Milton Keynes accident and emergency department in the early hours of Tuesday October 1 saying he had taken an overdose of tablets he had been prescribed for depression.
But he left before he could be seen and staff, worried about his safety, alerted police and his GP.
Dr Hopeson Alifoe, from Bletchley's Whaddon House surgery, told how he tried desperately to contact Mr Duca, calling round his house and even breaking his ethical code by telling the family why he was so worried.
He finally managed to speak to Mr Duca on his mobile phone, in the middle of the afternoon, to persuade him to come into the surgery. But minutes later Mr Duca was found in his car on a Mursley cycleway trying to commit suicide.
Passer-by David Thrower told how he opened the car door to let the lethal fumes out and tried to persuade Mr Duca to disconnect the pipe. But he said, Mr Duca shut the door and drove off.
Police intercepted him and drove him to the Tindal psychiatric centre in Aylesbury where he was seen by consultant psychiatrist Dr Vergis Thomas.
Shortly after 5.30pm he was sent home with two sleeping pills, a follow up appointment and his car keys.
Dr Thomas admitted to the inquest that 'in hindsight' this was probably the wrong decision.
The following lunchtime Mr Duca was found by his neighbour, hanging from a ligature made from a leather belt, in his garage.
The inquest heard Mr Duca, a solitary bachelor who owned several properties, had been depressed because he thought he had made some bad business decisions and could not get his life in order.
A verdict of suicide was recorded.