Dr. Conrad Murray was charged yesterday (2/8) with involuntary manslaughter in the death of Michael Jackson.

Murray, a cardiologist caring for Jackson during preparation for his "This Is It" concert run, pleaded not guilty in a courtroom near Los Angeles International Airport, according to the Los Angeles Times.

The long-awaited charge in the superstar's June 25, 2009 death is the least serious homicide charge available to prosecutors. If convicted, Murray will face a maximum of four years in prison, compared to 11 years for voluntary manslaughter.

To convict on an involuntary manslaughter charge, prosecutors only have to prove that the death occurred during an "unlawful act not amounting to a felony" or during a lawful act performed "without due caution or circumspection," according to the Times. Prosecutors do not have to prove Murray acted with malice or intent.

The coroner's office, which previously said Jackson died from "acute propofol intoxication" in combination with the use of sedatives, released a full report on Monday (2/8) that described the level of anesthetic as enough to render a patient unconscious for major surgery.

Murray's bail was set at $75,000 and his lawyer told the media he is expected to resume seeing patients in Las Vegas later this week. The terms of his bail specifically forbids him from prescribing propofol or other heavy sedatives. The judge told Murray, "I don't want you sedating people."

In California, the attorney general has moved to revoke Murray's medical license while he awaits his trial, according to a Good Morning America report. Murray is expected to next appear in court in April.

The charge against Murray--and his "not guilty" plea--was met with very negative responses from Jackson's family. "He's lying. He's guilty. Nobody was there but him," Jackson's mother, Katherine, told the assembled media while leaving the courthouse. "He's just trying to save his own behind. … He killed him. He wasn't monitoring him."

The reactions from Jackson's father, Joe Jackson, and sister, La Toya Jackson, go one step further, alleging MJ was murdered and that Murray was part of a much larger plan.

"To me, he's just a fall guy," Joe Jackson told CNN's Larry King. "There's other people, I think, involved with this whole thing."

Joe Jackson said Michael told his mother that he feared he would be killed in the lead-up to his London shows. "He was afraid to even do all of these shows, because he was afraid that he wouldn't get a chance to finish all of the shows," Joe Jackson said. "Even his kids say that he had told them that he would be murdered."

When pressed by King to elaborate, the Jackson patriarch did not specify who might be involved, saying only that "someone" hired Murray.

La Toya Jackson, who has long held the belief that her brother was murdered, issued a statement later in the day that said she believes Murray was part of a much larger plan. "There are other individuals involved, and I will not rest and I will continue to fight until all of the proper individuals are brought forth and justice is served." As with her father, La Toya did not elaborate on her allegations and has not named any other suspected conspirators.

Police have not named any other suspects in Jackson's death.