Murray is the target of what police term a manslaughter investigation but the probe is far broader, encompassing a half-dozen doctors who treated Jackson over the years. Police and federal Drug Enforcement Administration agents are trying to reconstruct Jackson’s extensive drug history, a task made more difficult because the pop star used pseudonyms to obtain medications.

Tracking down where Jackson got drugs, who provided them, how much his prior drug use contributed to his death and lining up experts to distill complex medical information into layman’s terms for a jury is time-consuming.

“There’s no reason for anyone to jump the gun on this,” said Greg D. Lee, a retired supervising DEA agent. “Time is on their side. There’s no imminent danger to the public from Dr. Murray.”

The decision on criminal charges will come from the Los Angeles County district attorney’s office. Spokeswoman Sandi Gibbons said a request for charges comes after a police investigation is completed and prosecutors examine the evidence themselves. “We haven’t been presented with anything,” she said.

Except for a brief video posted to YouTube, Murray has not spoken publicly since Jackson’s death. In the video, he said: “I told the truth and I have faith the truth will prevail.”

Murray’s attorney, Edward Chernoff, did not return a message seeking comment but previously has said nothing Murray gave Jackson “should have” killed him.

Murray has been interviewed twice by police. According to court records, he told investigators that over about six hours he injected Jackson with two doses each of lorazepam and midazolam. Finally, around 10:40 a.m. on June 25, Murray said he succumbed to Jackson’s demands and administered propofol, a drug Murray said he had given Jackson every night for six weeks to allow him to sleep.

Propofol commonly is used to render patients unconscious for surgery. It’s only supposed to be administered by anesthesia professionals in medical settings and, because of its potency, requires the patient be closely monitored at all times. Using propofol strictly as a sleep agent violates medical guidelines.

The coroner’s finding of homicide, or death at the hands of another, does not automatically mean a crime was committed. To bring a manslaughter charge, prosecutors must show there was a reckless action that created a risk of death or great bodily injury. If a doctor is aware of the risk, there might also be an issue of whether the patient knows that risk and decided to take it.

Dr. Jayson Hymes, an anesthesiologist and specialist in pain medication and addiction, said authorities are confronted with a central question: “It’s not illegal to be a bad doctor but when does it go from bad medicine to so unbelievably stupid it’s criminal negligence?”

He said investigators may be questioning Murray’s claim that he was trying to “wean” Jackson off the powerful anesthetic by giving him decreasing doses.

“It makes no sense,” said Hymes. “You don’t wean people off propofol. People don’t go around craving propofol. What he needed to be weaned off of were all the other drugs.”

As for Jackson’s demand for propofol, he said, “He didn’t understand that anesthesia is not sleep. If he wanted restorative sleep, he was going in the wrong direction.”

Los Angeles attorney Harland Braun, a celebrity defense attorney who also has represented doctors in court, suggested prosecutors may take the case to a grand jury and let it investigate the evidence and recommend action.

Loyola University Law School professor Laurie Levenson said history hangs over prosecutors as they build the case. The district attorney’s office is shadowed by memories of the O.J. Simpson and Robert Blake murder acquittals and the Phil Spector case that took two trials to win a second-degree murder conviction.

Prosecutors will want to make sure they have a very strong case before proceeding.

“There’s no question that a bad thing happened,” she said of Jackson’s death. “But you need to prove to 12 jurors beyond a reasonable doubt that it is manslaughter. That’s a very high threshold.”

Vesna Maras, a former Los Angeles deputy district attorney who spent 12 years trying medical and pharmacological cases for the office, noted it is not illegal to simply administer propofol.

“If he didn’t research the drug that would be conscious disregard of the risk to human life, which is second-degree murder,” she said. “If he did research it, was aware of the risks and didn’t exercise due caution and circumspection before administering it, that is involuntary manslaughter.”

Criminal defense attorney Steve Cron cited the fact other agencies including the DEA have simultaneous probes involving other doctors who prescribed medications to Jackson and pharmacies that filled the prescriptions. If all investigations must be completed before charges are filed, it could take considerable time.

In the Anna Nicole Smith drug case, it took authorities 2 1/2 years to bring charges against her doctors and boyfriend. And the counts were less serious — supplying drugs to an addict.

Lee noted once charges are filed, “the clock starts ticking” on statutory time limits for prosecution. So, “what’s the rush?” he said. “I don’t see any urgency on the part of the government.”

(This version SUBS graf 17 to correct to second-degree murder FROM manslaughter.)