But the anticipating public shouldn't hold its breath. As with the long line of celebrity overdoses that came before, like Michael Jackson, Heath Ledger and Anna Nicole Smith -- toxicology reports pronouncing the cause of death for these two young celebrities will not be released for weeks, possibly months.
But experts say the delays are often caused by a combination of overwhelmed toxicology labs, and cautious prosecutors, not by the length of the testing procedures.
Does it really take that long to run most of these drug tests? According to forensic pathologist to the stars, Dr. Cyril Wecht, "Certainly not."
"It does not take several weeks," says Wecht. "That's sheer nonsense. Most of the time they tell the media that to get them off their backs.
"If the autopsy is done in the morning, the specimen is at the lab by lunchtime, and in my opinion, within 48 hours -- once the test are started -- they have a pretty good idea of what drug and how much," Wecht says concerning cases involving prescription drug overdoses.
"We're not dealing with rare cobra venom or the saliva from a South American frog," he adds. "We're dealing with Demerol or Oxycodone -- these are drugs people take all the time."
In an emergency room, he points out, "they will draw blood and submit to their lab and they'll have responses back in a few hours, because it's a matter of life or death [they need to know] how to treat the patient."
While he admits that a long line of backlogged cases can contribute to the delays often experienced at toxicology labs, in the case of basic drug tests for high profile deaths, "I guarantee you, within one to two days, they've got the results back on their desks."
But often autopsy toxicology tests -- even for overdoses of common drugs -- can be more complicated than expected, toxicologists say.
According to Ruth Winecker, chief toxicologist for the state of North Carolina's Office of the Chief Medical Examiner, the scope of laboratory testing for a forensic screening is much wider than for hospitals.
"Hospital clinical labs generally are screening for five to 10 drugs but...a forensic lab is screening for several hundred drugs and toxic substances."
Additionally, toxins or drugs for an autopsy report have to essentially be tested twice, once in the initial screening and once in a confirmation assay, which will "unequivocally identify the drug or toxin and quantify the amount present," Winecker says.
Unlike medical cases in emergency rooms, toxicologists have to produce results that are "valid, reliable, and defensible in a court of law," says Dr. Bruce Goldberger, director and professor of toxicology at the University of Florida. To get the kind of conclusive results necessary, "many of the procedures utilized take days to perform," he says.
Add on top of this, experts says, that forensic toxicology laboratories are under-resourced and understaffed, and the build-up of cases can be overwhelming.
"There is usually a backlog...that will delay the start of testing on new cases," says Winecker, and most laboratories have a backlog reaching back weeks or even months, Goldberger adds.
The lack of necessary resources has a lot to do with the expense of modern procedures.
"Testing for drugs is a very expensive endeavor and appropriate funding sometimes becomes an issue," Goldberger points out, adding that there is a lack of "qualified and competent forensic toxicologists" in this country.
Even with short resources and long backlogs, is there a way to expedite the process?
"You can move to the head of the line but it is a rare occurrence -- we have only expedited cases a handful of times in the 13 years I have been with the Office of the Chief Medical Examiner," Winecker says.
But often, experts say, investigations into celebrity deaths do end up being expedited.
"If you have a Brittany Murphy or a Michael Jackson case, within just a few days after the autopsy, there is sufficient information to determine a cause of death," Goldberger says.
Wecht agrees. "I find it hard to believe that in a Michael Jackson, Anna Nicole Smith, or Heath Ledger scenario, that those cases are not going to be placed in front of the line -- they are."
"Is that fair?" he adds. "It's an ethical question. From a pragmatic perspective, if I'm making a decision, I'm going to put them at the head of the line. The whole world is waiting [and for] the average citizen, another day or two isn't making a difference."
But while those investigating a celebrity death may know in a matter of days, the results still will not be made public for weeks.
Part of the reason for this delay is that toxicologists cannot responsibly release the cause of death until the case is finalized, Goldberger says.
Until all the results are in -- a feat which can take weeks to accomplish -- "that doctor is not going to certify the death," he says.
And if a crime is implicated, "the autopsy report can be held indefinitely," which is the case in Michael Jackson's death. Though the tests have "been done for months," says Goldberger, the official report has still not been released.
While the customary six- to eight-week delay in celebrity autopsy reports may keep a guessing public waiting, for the average person with a drug-related death in the family, the wait is in the order of months and even years.
"If Mr. Average Citizen dies today, that body might stay there for a week or two before they get to it -- and if they're that far behind with the bodies, how far behind do you think they are with drug testing?" says Wecht. "Labs are months and months behind."
"I have around 400 cases that have not been fully processed yet," notes Goldberger.
"This is being experienced by hundreds of families in America every day: they're waiting and waiting and not getting any answers," Wecht says.
The same holds for rape cases. "I should have a hair on my nearly bald head for every 1,000 rape cases that line labs throughout America that have been collected and are lying on counters that haven't been tested, and maybe will never be tested," Wecht says.
"These are very important matters. We're dealing with life and death and families who have suffered tremendous emotional stress and trauma and grief.
"On 'CSI,' five or six people are working a case and the public is totally misled -- this is so far from reality, it's unbelievable."
The reality is that "forensic science labs are being short changed in every state [and] at the federal level," Wecht says.
He adds, "Somebody has to decide if it's more important to pay an actor $100 million a year or to find a serial rapist -- it has to do with our priorities in America."