Dr. Conrad Murray speaks with his attorney, Ed Chernoff, during his trial in the death of pop star Michael Jackson Oct. 3, 2011, in Los Angeles. (Mario Anzuoni/Pool/AP Photo)

ABC News’ Colleen Curry and Jim Avila report:

Attorneys for Dr. Conrad Murray will present 16 witnesses and a three-pronged defense of Michael Jackson’s personal doctor this week as they begin their defense today in Murray’s manslaughter trial.

Jackson died two years ago from an overdose of the powerful anesthetic propofol. Murray has admitted to giving the singer the anesthesia June 25, 2009, and said the singer begged for his “milk,” the nickname he’d given for the creamy drug. The doctor could face four years in prison if convicted of involuntary manslaughter.

The defense is expected to start its own case today with two police detective witnesses and the promoter of Jackson’s This Is It tour, Randy Phillips. They are expected to call 16 witnesses in all this week, including  an expert in anesthesia, Dr. Paul White, their star witness.

White, however, has already been heard from during the trial, when he was chastised by Judge Michael Pastor for talking to reporters about the trial.

E! online reported that Murray could be heard whispering loudly to the possible witness, Dr. Paul White, “Can you believe that?” in response to the testimony of Dr. Steven Shafer, a witness for the prosecution. In response, White allegedly turned to journalists and said, “What a scumbag.”

It was unclear whether White was referring to Shafer or prosecutor David Walgren.

Pastor scolded White for his remark and set a Nov. 16 hearing date to determine whether White should be held in contempt of court.

In addition to White’s testimony about anesthesia, attorneys say they have to prove three things during their testimony: that propofol can be used safely as a sleep aid, that Murray did not have to immediately call 911 because he was busy tending to Jackson, and that Jackson was such an experienced drug user, he could have administered the propofol by himself.

For the latter point, lawyers will have to disprove prosecution witness testimony and convince jurors that the groggy Michael Jackson could have grabbed and swallowed a fatal dose of sedatives, or released the clamp on the propofol IV to self-administer a fatal dose of propofol.

They will also have to prove that Murray’s time was better spent trying to help Jackson in the moments after the doctor discovered him unconscious rather than calling 911 and waiting for emergency responders.

Testimony for the defense is expected to last all week.