For authorities investigating Michael Jackson’s death, more could end up meaning less, people.com reports.

If the entertainer’s autopsy report reveals other potent drugs besides the powerful anesthesia Propofol, as has been widely reported, prosecutors will have a more difficult time building a manslaughter case against Jackson’s private physician, experts say.

In short: More drugs, potentially less criminal responsibility for Dr. Conrad Murray.

“You have to show that the doctor knew about all of these other doctors prescribing these other drugs,” said one Los Angeles deputy district attorney who prosecutes doctors. “It’s a classic problem.”

Murray, who reportedly admitted to police that he administered the anesthetic, has not been charged. Search warrants served to Murray indicate he’s the target of a manslaughter investigation.

Although many anesthesiologists say it’s negligent and unusual for a doctor to administer Propofol in a home without proper monitoring, legal experts say that fact alone might not be enough to prosecute Murray for more than an administrative-code infraction if it can’t be proven that the Propofol alone was what killed him.

According to the Los Angeles Times, Jackson’s toxicology report revealed a few drugs, such as the anti-depressant Xanax, in addition to Propofol. Legal experts say this helps explain why, seven weeks after Jackson’s death, no charges have been filed and authorities are keeping mum.