After a lengthy trial, Dr Conrad Murray has been sentenced with committing the involuntary manslaughter of singer Michael Jackson. Murray prescribed the star with probofol — a hospital-grade sleep drug — as well as a range of other sleep medication that consequentially led to Jackson’s death.

For those not in the legal know, involuntary manslaughter is an ambiguous phrase. So Crikey put the term to the experts to translate the legal jargon …

What is the difference between murder, manslaughter and involuntary manslaughter?

All three charges result from the same outcome — a person dies as a result from someone’s actions. Proving the state of mind — or mens rea, in legal terms — of the suspected murder is crucial in determining whether their charge will be upheld in court.

For a murder charge to stick, the prosecution must prove the murderer had the deed mentally planned before committing the crime.

As Monash University’s Dr Bronwyn Naylor explains, the step down from murder to manslaughter involves a defence. She clarifies manslaughter as: “They killed intending to kill, but they have a defence, like provocation or self-defence … a partial defence.”

Dr Naylor says the reduction to involuntary manslaughter revolves around the murder not having any motive to kill the victim. “It’s where someone kills somebody, but they don’t intend to cause that level of harm.”

Melbourne University’s Kevin Jon Heller says there are two forms of involuntary manslaughter: “An unlawful or dangerous act that that causes someone to die” — for example, accidentally hitting someone with your car — and “criminal negligence, a lawful act with gross negligence”.

Conrad Murray giving prescribing Michael Jackson probofol is a good example of this. He didn’t mean to kill him, but a poor decision as a medical practitioner led to Jackson’s death.

But as Dr Naylor warns, there has to be some level of fault for there to be a charge. “If it was absolutely accidental, then none of our legal systems would convict the person. We take the view that if you are going to be guilty, you have to have some level of fault,” she said.

What are the sentences for involuntary manslaughter?

Each state in Australia has different legislation in relation to manslaughter. Victoria, for instance, does not qualify between voluntary and involuntary manslaughter.

Jail sentences for manslaughter vary across Australia. In Victoria, there is no minimum sentence for manslaughter while the maximum penalty is 20 years in jail. In NSW it’s 25 years, while in Queensland and South Australia life in prison is the maximum sentence.

Dr Naylor says in states where involuntary manslaughter is not legislated, a lack of motive would serve as a factor that would reduce a manslaughter sentence.

What are the differences between American and Australian law?

It’s complex to draw a comparison between Australian and American law since each state in both countries has their own set of laws and penalties. The major difference is that California law — the law Conrad was tried to –distinguishes between voluntary and in-voluntary manslaughter.

Heller, who has practised law in America, says being found guilty of involuntary manslaughter would involve a sentence of between two and four years in  jail. A guilty verdict of voluntary manslaughter would incur a sentence of between three and 11 years in jail.