Investigators from Detroit have asked the CBS TV network to give them the uncut video tape recording made by Doctor Jack Kevorkian as he injected 52 year-old Thomas Youk with lethal drugs.

Provoke a showdown: Dr Kevorkian wants authorities to act

Mr Youk, who was suffering from an irreversible wasting disease, had asked Dr Kevorkian, known popularly as Dr Death, to end his life.

Dr Kevorkian says he has helped more than 120 people to die.

But prosecutor David Gorcyca has accused Dr Kevorkian of a lack of compassion:

'After viewing the edited portions of the video last night, it appeared a homocide was committed in violation of the laws of the state of Michigan," Mr Gorcyca said.

"However, a charging decision will not be made until the video tapes are viewed in their entirety."

Dr Kevorkian, a 70-year-old retired pathologist, has been tried and acquitted four times for helping terminally ill patients to die.

BBC's Brian Barron: "He says if he's jailed, he'll go on hunger strike"

He says he wants to provoke a legal showdown, although his former lawyer Geoffrey Feiger is trying to avert another courtroom battle.

Mr Feiger said: "Dr Kevorkian has served a valuable purpose in bringing this issue to the fore in terms of the needs of suffering people.

"But I don't think he will serve any purpose by martyring himself."

Two drugs

The footage screened on CBS's 60 Minutes showed the patient, Thomas Youk, of Detroit, Michigan, twice signing a consent form after Dr Kevorkian asked whether he wanted the lethal injection to go ahead.

Viewers saw Dr Kevorkian administering two drugs, one to make the patient sleep and one to stop his heart.

In the broadcast, reporter Mike Wallace asked Dr Kevorkian, "You killed him?"

The doctor replied: "I did, but it could be manslaughter not murder.

"It doesn't bother me what you call it. I know what it is."

Some of Mr Youk's family took part in the 60 Minutes programme. His wife Melody said: "I was so grateful to know that someone would relieve him of his suffering.