Two of Michael Jackson's children watched horrified as the pop star lay motionless on his bed the day he died, a bodyguard for the pop star said in emotional testimony

"Paris (Jackson) screamed 'Daddy' and she started crying, and Dr. Murray said, 'Get them out, don't let them see their father like this,'" Alberto Alvarez told a Los Angeles court.

Alvarez was testifying on the second day of a preliminary hearing that will decide if Conrad Murray, Jackson's personal doctor, should stand trial for involuntary manslaughter.

The court also heard that Jackson appeared dead when paramedics arrived, and that Murray made no mention to first responders that the singer had used the powerful anesthetic propofol.

Alvarez said he was alerted by phone on June 25, 2009, that something was wrong with Jackson He entered the pop star's room and saw Murray at the bedside. The doctor told him they needed to get an ambulance, Alvarez said.

The security guard said he was reaching for his cell phone, when he saw that Jackson's eldest two children, Prince and Paris, who were then 12 and 11, had walked into the room.

"I turned to the children and I told them, 'Don't worry children, we'll take care of it, please go outside.' And I escorted them out of the bedroom," Alvarez said.

Alvarez said Murray told him Jackson had "a bad reaction," and ordered him to bag up medical vials and an intravenous pouch before calling paramedics.

"He (Murray) then grabbed a handful of bottles or vials and instructed me to put them in a bag," Alvarez said.

Prosecutors are seeking to establish that Murray was negligent in his treatment of the "Thriller" singer and tried to cover up his errors. Murray had been hired to care for Jackson before his planned comeback concerts in London.

Murray has pleaded not guilty to involuntary manslaughter but has admitted giving the 50-year-old singer a dose of propofol as a sleep aid, at Jackson's request.

Coroners officials say the "King of Pop" died of a drug overdose, due mainly to acute intoxication of propofol.

Murray's attorney, Ed Chernoff, suggested to Alvarez on Wednesday that Murray could have intended to bring the medication to the hospital, or set it aside to make room for the paramedics.

Alvarez said Murray told him to take away an intravenous bag that had "a milky substance" inside, and put it with the other bottles in a plastic bag that was placed inside a canvas carrying case. He said he did not know where the bags went.

Members of Jackson's family, including sisters Janet and La Toya, mother Katherine and father Joe, watched the testimony on Wednesday.

Paramedic Richard Senneff, who responded to Jackson's home, said he found Jackson motionless. He added that Murray never told him the singer had taken propofol, despite being asked if Jackson was on any medication.

"I don't often see an IV pole and a doctor on hand," Senneff said. "The patient appeared to be pale and underweight, I was thinking along the lines that he was a hospice patient."

Senneff said Murray only admitted to administering the sedative Lorazepam.

Prosecutors have claimed that more than 20 minutes elapsed between the time Murray found Jackson motionless in his bed at his rented Los Angeles mansion, and the calling of paramedics.

Senneff said his crew detected no pulse, and that based on Jackson's dilated pupils and cold limbs, it appeared his heart had stopped more than 20 minutes before.

The preliminary hearing is expected to last up to two weeks.