Katherine Jackson, Michael Jackson's mother, leaves court after a hearing for Jackson's doctor, Conrad Murray, Thursday Jan. 6, 2011 in Los Angeles.

*Dr. Richelle Cooper testified yesterday that she was sure Michael Jackson was dead before paramedics wheeled him into her emergency room at Ronald Reagan UCLA Medical Center, and more than an hour’s worth of resuscitation efforts didn’t change her opinion, according to the Associated Press.  The King of Pop had died in the bedroom of his rented mansion.

Based on what Jackson’s personal physician Conrad Murray told her, though, she didn’t quite know why.

Cooper testified Thursday that Murray told her he had seen Jackson stop breathing and immediately started CPR, but prosecutors say that’s not what happened.

In the past three days, prosecutors have called a dozen witnesses at a preliminary hearing who laid out a timeline in which Murray delayed calling 911 while he collected and bagged medications.

Cooper also testified that she had authorized paramedics by phone to pronounce Jackson dead at 12:57 p.m. at the mansion, but they declined at Murray’s request and because of the singer’s celebrity, saying they would prefer it be done at the hospital.

After an ambulance ride trailed by paparazzi, and more than an hour of efforts in the emergency room, Cooper officially pronounced Jackson dead at 2:26 p.m. on June 25, 2009.

She said Murray never told her he had given Jackson the powerful anesthetic propofol, which Cooper said she typically uses for patients with head trauma or serious injuries.

Authorities contend that Jackson died after Murray gave him a lethal dose of propofol and other sedatives at the mansion. Murray has pleaded not guilty to involuntary manslaughter.

Cooper said the Houston-based cardiologist also didn’t mention several other sedatives he administered.

Murray’s defense attorney, J. Michael Flanagan, asked Cooper if propofol use would be relevant information, since the drug wears off quickly.

Cooper said it wouldn’t have changed her efforts to revive Jackson, but knowing that Murray had given the singer several sedatives and propofol would have added to her understanding of why the singer had died.

Cooper said other sedatives could have amplified the effects of the propofol and caused Jackson to stop breathing before his heart stopped beating.

“I would be concerned particularly if there were other medications given, that it would lead to a respiratory arrest, which would lead to a cardiac arrest,” Cooper said.

LaToya Jackson, sister of Michael Jackson, leaves court after a hearing for Jackson's doctor, Conrad Murray, Thursday Jan. 6, 2011 in Los Angeles.

The testimony came during a preliminary hearing after which a judge will decide if there is enough evidence for Murray to stand trial. He could face up to four years in prison if tried and convicted.

Paramedic Martin Blount, who also testified Thursday, said he saw Murray scoop up three vials of the painkiller lidocaine from the floor of Jackson’s bedroom during resuscitation efforts.

Blount said he was surprised to see the medications because Murray had told him that he hadn’t given the singer any drugs.

Murray’s attorney, Joseph Low IV, did not question Blount’s description of the lidocaine.

Nicole Alvarez, a girlfriend called by Murray while riding in the ambulance to the hospital, has been ordered to appear in court today. The hearing will also feature detectives, coroner’s officials and experts on propofol’s effects.

Before the hearing is over, a judge might hear Murray’s version of events as well, as told to police detectives three days after Jackson’s death.

Deputy District Attorney David Walgren has said he will use Murray’s statements and testimony to show his actions represented “an extreme deviation from the standard of care.”

Meanwhile, cell phone records shown in court Thursday also show that Dr. Murray was talking on the phone and texting during the period authorities say he should have been closely monitoring Jackson’s vital signs.

The records presented by prosecutors indicate that Murray made or received 11 phone calls over five hours while at the singer’s rented Holmby Hills mansion, including a trio of back-to-back conversations that lasted 45 minutes and were interrupted, prosecutors have said, only by Murray’s sudden realization that his famous patient had stopped breathing.

Prosecutors have accused him of making an “extreme deviation” from the standards of medical care by, among other things, administering the surgical anesthetic propofol without proper monitoring. The specifics of Murray’s treatment remain something of a mystery because Jackson barred everyone except his children and the doctor from the second floor of his residence. But with the records, prosecutors suggested that Murray was distracted from his medical duties by the calls and other text messages.