A French doctor has admitted turning off the life support machine of a severely disabled man who had expressed a desire to die.
Humbert wanted "neither suffering, regrets nor tears"
Vincent Humbert, who was left mute, blind and paralysed after an accident three years ago, lapsed into a coma after being given an overdose by his mother last Wednesday. He died on Friday.
The doctor, Frederic Chaussoy, said it was common for medical staff to take similar decisions but there was a "tradition of hypocrisy" about revealing them.
His admission came as mourners attended Mr Humbert's funeral in the northern town of Berck-sur-Mer.
Mr Humbert planned the ceremony himself, which included his favourite song, by French singer Michel Berger, and readings by close friends and family.
His father read out a "last message" from his son, saying he wanted "neither suffering, regrets, nor tears".
"I want them to accept my departure as a very simple thing,
very natural," the message read.
Euthanasia is illegal in France, and although the government has ruled out a change in the law, spokesman Jean-Francois Cope said it was open to debate on the issue.
Mr Humbert's mother, Marie, was briefly arrested on Wednesday, then released into psychiatric care. She had injected her son with barbiturates after announcing in advance her intention to do so.
Prosecutors have been considering whether to charge Mrs Humbert with murder or manslaughter.
But Dr Chaussoy said that he had now been summoned for questioning by police and could face a formal investigation.
He and his team had agreed to switch off the machine, he added, describing the decision as "painful".
"I take the responsibility for this act," he told Europe 1 radio. "It was a sad but carefully thought-out decision taken with serenity and with respect for the patient."
"We know very well how to lie. We do it regularly and we could just have continued this tradition of hypocrisy, but in this case it was better to tell the truth."
Mr Humbert wrote to President Jacques Chirac last year, asking him permission to end his life.
The request was turned down, but the publicity ignited a fierce debate in France over whether the law forbidding assisted suicide should be changed.
Polls believe Marie Humbert was right to carry out her son's request
Last Thursday, his book I Ask for the Right to Die was published in France, describing intense frustration at what he called a "living death".
He wrote the book using his right thumb, the only part of his body he was able to move, to indicate the letter of the alphabet he wanted.
Opinion polls suggest that the majority of French people believe Mrs Humbert was right to carry out her son's request.
The BBC's Caroline Wyatt says that following the tragic case, more than 80% of respondents say the law against voluntary euthanasia should now be changed.
In a similar case, British doctor David Moor said in 1999 he did not regret hastening by injection of painkillers the death of a terminally ill cancer patient two years earlier.
After being cleared of the murder of 85-year-old George Liddell, he said he would go through the ordeal of a trial again.