In addition, it turns out Murray's father once was embroiled in a controversy over drugs and patients, as well. Murray's father once ran afoul of the Texas Board of Medical Examiners for over-prescribing pain medications, ABCNews.com reported.
An involuntary manslaughter charge, which law enforcement sources have told ABC News is the mostly likely charge to come out of the Murray investigation, means the person charged did not intentionally cause the death but knew his or her actions were risky enough to do so.
Former Jackson attorney Mark Geragos told "Good Morning America" today that in addition to involuntary manslaughter, Los Angeles-area law enforcement officials in cases similar to Jackson's have been known to levy a charge of "implied malice murder."
"Which means," Geragos said, "somebody didn't intentionally mean to kill someone but acted so recklessly" that it could constitute a murder charge.
Investigators believe that someone was intravenously administering propofol, a powerful sedative, to Jackson at his home.
Medical experts have soundly agreed that a drug like propofol, which is typically used in the hospital to sedate patients for surgery or other medical procedures, should not be used in the home, something Geragos said could be very damning to the doctor who prescribed it to Jackson.
"If you've got a drug that's found in the house and somehow that drug was obtained by Michael Jackson or someone around Michael Jackson … that would be something that is so reckless and so wildly beyond the standard of care that legally that would supply an implied malice," he said.
Geragos said he's also stunned that so many of Jackson's doctors and health professionals have been talking about their treatment of the singer while the investigation is ongoing, especially Murray, who has issued several statements through his lawyer.
"They've got him in the crosshairs, so to speak, and they want to prosecute someone," he said.
Though Murray's lawyers have maintained for weeks that the doctor was simply a witness in Jackson's death, the raid in Houston suggests the investigation has shifted to something more.
"It's never a good thing to have DEA agents, police both local and out of state come into your business," said ABC News consultant Robert Jakucs, who is retired from the Los Angeles Police Department. "The fact that a search warrant is being served on an individual oftentimes leads to the idea that he was a suspect."
Murray, Jackson's personal physician hired to monitor the entertainer for his "This Is It" tour, was called to Jackson's house the day before he died and was the person who found him unconscious, not breathing in bed the next day.
Murray has been widely criticized by medical professionals for waiting more than 30 minutes to call 911 and for performing CPR on a bed instead of a hard surface, but he has continually denied giving Jackson any drug that could have killed him.
He has been secluded at his Las Vegas home and reportedly goes out with a security detail due to death threats.
"Any physician who's administering propofol in the home should be subject to sanctions," said Dr. Joshua Prager, a pain specialist at the University of California at Los Angeles.
Lee spoke out in the days following Jackson's death about how she turned down his increasingly desperate pleas for propofol, a powerful anesthetic that reportedly led to Jackson's death.