Dr Kevorkian, often referred to as Dr Death in the world's media, was charged with giving a lethal dose to a terminally ill man whose death was shown on national television.

Stephen Sackur: The law has caught up with Dr Kevorkian

The jury in Oakland County Circuit Court in Michigan rejected Dr Kevorkian's arguments that his intent was not to murder Thomas Youk, 52, but rather to end his suffering.

Dr Kevorkian, who has previously threatened to go on hunger strike if convicted and jailed, remains free on bail until his sentencing on 14 April. He could be jailed for any term up to life in prison.

He plans to appeal the verdict, a process which could take years.

Prosecutors had sought a first degree murder conviction which carries a mandatory life sentence.

Thomas Youk: Death shown on US TV

Dr Kevorkian showed no visible reaction as the verdict was read. He has previously threatened a hunger strike if convicted and jailed.

The 70-year-old retired pathologist says he has helped more than 130 people die since 1990.

He has been acquitted by three juries on assisted suicide charges. A mistrial was declared in a fourth trial.

In past cases, Dr Kevorkian has said his clients used his homemade devices to start the flow of carbon monoxide or intravenous chemicals that caused their death. In Mr Youk's case, Dr Kevorkian administered the injection.

Death on TV

Mr Youk, who had a wasting disease, was confined to a wheelchair and had difficulty breathing and eating.

Dr Kevorkian provided the television programme "60 Minutes" with a video recording of his death.

He had hoped to call the widow and brother of Mr Youk to prove his argument that his intent was not to kill him but rather to end his suffering.

But Judge Jessica Cooper blocked them from testifying.

She ruled that their testimony relating to Mr Kevorkian's intent and Mr Youk's consent would be irrelevant in a murder case.

Clashing closing arguments

The jury deliberated for a day and a half before delivering its verdict.

Frequent clashes: Mr Kevorkian and Judge Cooper

In his closing statement, Kevorkian compared himself to civil rights heroes Martin Luther King and Rosa Parks and he reminded the jury that in the past acts including drinking beer and registering to vote were illegal.

"Words on paper do not necessarily create crimes," he said.

He told jurors that if they convict him, they would face "the harsh judgement of history, and the harsher judgement of your children and grandchildren if they ever come to that precious choice".

Prosecutor John Skrzynski objected several times during Mr Kevorkian's closing statement, arguing that the assisted suicide advocate was trying to introduce new testimony.

In the prosecution's closing arguments, Mr Skrzynski referred to Mr Kevorkian as a "medical hitman".