LOS ANGELES (AP) — Michael Jackson's doctor pleaded not guilty Monday to involuntary manslaughter in the death of the pop star at a brief hearing that had all the trappings of another sensational celebrity courtroom drama.

Dr. Conrad Murray, accused of giving Jackson a fatal dose of an anesthetic to help him sleep, appeared in court in a gray suit and burgundy tie as Jackson's father Joe, mother Katherine, and siblings LaToya, Jermaine, Tito, Jackie and Randy watched from courtroom seats behind prosecutors.

Neither Murray nor the Jacksons showed much emotion as the six-foot-five Murray entered his plea through his attorney Ed Chernoff, but as he emerged from court, Joe Jackson declared, "My son was murdered."

"We need justice," he added before leaving with family members in a fleet of Cadillac Escalades.

Earlier, several people shouted "murderer" as Murray walked past a crowd of hundreds of reporters and Jackson fans on his way to a courthouse adjacent to Los Angeles International Airport. Others held signs urging "Justice For Michael."

Murray, 56, a Houston cardiologist who was with Jackson when he died June 25, entered his plea just hours after he was charged.

Superior Court Judge Keith L. Schwartz set bail at $75,000, three times more than the amount people normally face after being charged with involuntary manslaughter. Murray posted it about two hours later and was released.

Chernoff said outside court that Murray plans to return to practicing medicine in Nevada and Texas while he awaits trial. The judge ordered him to return to court April 5 for a preliminary hearing.

"He'll be back in Vegas this week, he'll open his medical practice," Chernoff said.

The judge warned Murray he is not to use general anesthesia on anyone while he is free on bail.

"I don't want you sedating people," he said.

Deputy state Attorney General Trina Bell also told the judge the state Medical Board is planning to seek the suspension of Murray's medical license. The action would only affect his ability to practice medicine in California.

It appeared authorities were taking extra steps to ensure the arraignment did not become a media circus.

Lines were formed to gain admission to the courtroom, and the Jackson family was escorted in separately and seated before anyone else arrived.

Despite the precautions, the upcoming proceedings promise to be the focus of widespread attention, especially if the Jackson family continues to take a high-profile role.

Immediately after the hearing, Latoya Jackson issued a statement saying she believed her brother had been murdered and that others besides Murray were involved in his death.

"I will continue to fight until all of the proper individuals are brought forth and justice is served," she said.

Jackson, 50, hired Murray in May to be his personal physician as he prepared for a strenuous series of comeback performances.

Officials said the singer died in Los Angeles after Murray administered the powerful general anesthetic propofol and two other sedatives to get the chronic insomniac to sleep.

Murray is accused of the single felony count in a five-page complaint that said he "did unlawfully, and without malice, kill Michael Joseph Jackson" by acting "without due caution and circumspection."

The complaint contains no details on Jackson's death, but authorities have said the singer died after Murray administered the anesthetic and other drugs.

If convicted, the doctor could face up to four years in prison.

Known as "milk of amnesia," propofol is only supposed to be administered by an anesthesia professional in a medical setting because it depresses breathing and heart rate while lowering blood pressure.

Los Angeles investigators were methodical in building a case against Murray, wary of repeating missteps that have plagued some other high-profile celebrity cases, most notably against O.J. Simpson and actor Robert Blake, both of whom were acquitted of murder.

When prosecutors filed their criminal complaint Monday the coroner's office released its autopsy report on Jackson. The document, previously obtained by The Associated Press, found the singer was in relatively good health and died from acute propofol intoxication.

Dr. Selma Calmes, an anesthesiologist who reviewed the autopsy report at the coroner's request, said the level of propofol in Jackson's body was akin to what would be given for major surgery. After such a dose, a patient normally would have a tube inserted in the airway to help with breathing and be ventilated by an anesthesiologist.

"The standard of care for administering propofol was not met," she wrote.

Court documents state Murray told police he administered propofol just before 11 a.m. then stepped out of the room to go to the bathroom.

There is some dispute about what happened next. According to court filings, Murray told police that upon his return from the bathroom, he saw Jackson was not breathing and began trying to revive him.

But an ambulance was not called until 12:21 p.m. and Murray spent much of the intervening time making non-emergency cell phone calls, police say. The nature of the calls, which lasted 47 minutes, is not known.

Murray's lawyer has said investigators got confused about what Murray had told them, and that the doctor found his patient unresponsive around noon.

A large number of witnesses have been interviewed by police, including those who were present during Jackson's last days, those who worked with him in preparation for his series of comeback concerts, "This Is It," and members of his personal entourage, including his security guard and personal assistant.

The comeback concerts sold out in anticipation of Jackson's return as the "King of Pop" after years of odd behavior and a lengthy molestation trial that had overshadowed a lifetime in music. Despite years of self-imposed exile, he retained a huge, loyal following of fans overjoyed at the prospect of seeing him reclaim the glory he'd attained with albums like "Thriller" and songs like "Beat It!" and "Billie Jean."