New York (CNN) -- To prove involuntary manslaughter, prosecutors will have to convince jurors that Michael Jackson's doctor took risks he shouldn't have -- and that other doctors wouldn't have, legal experts say.
"It's not the same as malpractice," said Laurie Levenson, a professor at Loyola Law School. To prove a physician's actions are criminally negligent, she added, "it has to be really extreme for no good reason."
Jackson, 50, died on June 25 after Dr. Conrad Murray gave him several prescription medications over the course of a sleepless night, according to court records.
Murray, who was treating Jackson at the pop star's rented home, told police he then gave him 25 milligrams of propofol, a powerful anesthetic. Within minutes, Jackson was unconscious and had stopped breathing.
Murray, a cardiologist, told police he was worried that Jackson was becoming addicted to the drug and tried to wean him off it, according to a search warrant affidavit filed in the case.
Police recovered several bottles of propofol from Jackson's bedroom and from Murray's doctor's bag at the home. A search warrant executed last July on Murray's Las Vegas, Nevada, home and business turned up a receipt for propofol purchased on May 12, 2009, from a Las Vegas pharmacy. The propofol in Jackson's home was later linked by the manufacturer to bottles from the same as Vegas pharmacy.
Some legal experts say the fact that Murray was trying to get Jackson off propofol, also known as Diprivan, can be interpreted to imply he was aware the drug was harmful to his patient. It could be a key element in the prosecution's case.
"If you're thinking like a prosecutor, you can say he was completely on notice about the dangers of propofol," said Levenson. "He cut back the amount. He knew he was dealing with a very dangerous drug. Yet he administered it in Jackson's house without the proper medical equipment."
The drug should only be administered in a hospital setting, said an expert consulted by CNN.
"Propofol is very potent," said Dr. Bruce Spiess, an anesthesiologist at Virginia Commonwealth University. "The difference between what makes you unconscious and what makes you stop breathing is very little."
Murray is not the first physician to have provided propofol to Jackson, according to the search warrant affidavit. Jackson called the anesthetic his "milk."
Spiess, who is considered a leading expert in the field, said propofol is, indeed, milky in consistency and doctors refer to it "milk of amnesia" and "milk of anesthesia."
While propofol is safe in the right hands, Spiess said, there are risks so "it must be given by someone trained to administer it, and it must be given in a hospital or surgical center so that an anesthesia care provider can open your airway."
In Jackson's case, Levenson said, "It was an accident waiting to happen."
The key to proving involuntary manslaughter will be convincing jurors that Murray was negligent in the extreme, she said. "Ordinarily, criminal law doesn't pursue negligence. But because the harm is so great, the negligence is considered criminal."
Jurors don't have to get inside Murray's head to determine what he knew about the dangers of propofol, she said. It's what he should have known that makes the difference.
"Involuntary manslaughter is for clueless defendants," Levenson said. "It's the ultimate should-have-known-better charge. And the way you prove that is to put on a bunch of experts and independent witnesses to say he should have known better."
Investigators signaled months ago they were building a manslaughter case. The Los Angeles County coroner ruled Jackson's death a homicide and Murray's lawyer said search warrants he'd seen indicated investigators were seeking evidence of manslaughter.
Involuntary manslaughter cases are seldom brought and it can be difficult to explain criminal negligence in a way that resonates with jurors, experts said. As a result, many involuntary manslaughter prosecutions wind up in acquittals.
In recent years, involuntary manslaughter has been used successfully to win convictions against parents who leave their children in hot cars or fail to get them proper medical treatment.
Earlier this week, an Oregon couple who relied on faith-healing for a child who died was found guilty of negligent homicide -- that state's equivalent of involuntary manslaughter.
And on Wednesday, self-help guru James Ray was indicted on three counts of manslaugher in the deaths of three people during an Arizona sweat lodge ceremony.
"This was a terrible accident, but it was an accident, not a criminal act," said Ray's attorney, Luis Li. "James Ray cooperated at every step of the way, providing information and witnesses to the authorities, showing that no one could have foreseen this accident."
Involuntary manslaughter charges have occasionally been filed in cases involving doctors. Most involved physicians accused of writing excessive prescriptions for pain killers, sedatives or other powerful narcotics. Again, convictions have been few and far between.
Defense attorneys are likely to argue that other doctors prescribed the same medications to Jackson, Levenson said. "What the defense is going to do is drum up every doctor who ever gave strong medications to Michael Jackson and say, 'See, they did the same thing and he never had that reaction before.' "
California's standard jury instruction for involuntary manslaughter states that criminal negligence "involves more than ordinary carelessness, inattention or mistake in judgment." It can occur when a person acts in a reckless manner that creates a high risk of death.
In short, California defense attorney Jennifer Keller said, involuntary manslaughter "is reckless behavior that results in death."
"It is relatively rare to see involuntary manslaughter charged alone, unless it's vehicular manslaughter," she said.
Involuntary manslaughter carries a sentence of two to four years in prison. If convicted, Murray could lose his license to practice medicine.
CNN's Mallory Simon contributed to this story.