Los Angeles, California (CNN) -- A coroner's investigator testified Friday that she recovered a dozen bottles of propofol from the closet of Michael Jackson's bedroom, including an empty bottle found on the floor near his bed.
Propofol is the surgical anesthetic that the Los Angeles County coroner concluded killed Jackson when it was combined with sedatives given the pop star to help him.
Seven pill bottles containing prescription sedatives were found on the nightstand next to the bed where Jackson was sleeping, Coroner's Investigator Elissa Fleak said.
Fleak was the 16th witness to testify in the preliminary hearing, being held to decide if the involuntary manslaughter case against Dr. Conrad Murray will go to trial. Los Angeles County Superior Court Judge Michael Pastor will decide if there is "probable cause" to move the case forward. The hearing is expected to last two or three weeks with 20 to 30 witnesses.
Lead defense lawyer Ed Chernoff appeared to be using the hearing to probe prosecution witnesses for information that could help in a later trial, but he was admonished by Judge Pastor who told him "We're not on a discovery mission here."
"Houston, we have a problem," the judge said, interrupting Chernoff at one point. Chernoff and several members of the defense team are from Houston, Texas.
Murray's Los Angeles girlfriend was called by prosecutors to testify Friday, but she made it clear she knew little about the doctor's activities.
"Dr. Murray and I were on a need-to-know basis and I just know my place and my position in his life," Nicole Alvarez said.
Murray stayed in her Santa Monica, California apartment when he was in Los Angeles to work as Jackson's personal physician in the months before his death.
Murray is also staying at her apartment during his preliminary hearing, which is expected to last at least another week.
Alvarez, 29, met Murray at a Las Vegas gentleman's club where she was working in 2005, she said. They have a son together. He was born in March 2009, just three months before Jackson's death.
Her testimony was used to confirm that six FedEx packages sent by a Las Vegas pharmacy were delivered for Murray to her apartment over the two months before Jackson's death.
She was not asked about a phone call Murray apparently made to her as he was riding with Jackson in an ambulance the day he died.
A Houston cocktail waitress, Sade Anding, testified Friday that she was on the phone with the singer's doctor when the doctor suddenly stopped responding to her just before noon on June 25, 2009.
That is the moment prosecutors contend Dr. Conrad Murray first realized Jackson had stopped breathing
"I didn't hear him on the phone anymore," Anding said. "I heard commotion as if the phone was in a pocket and I heard coughing and I heard a mumbling of voices."
Anding stayed on the phone for another five minutes, listening and wondering why the man she sometimes dated wasn't responding, she said. "Hello, hello, are you there?" she testified she said.
The timing of the phone call is key to the prosecution's timeline of when Murray realized his famous patient was dying. Based on testimony so far, the moment came about 11:57 p.m.
The coroner concluded Jackson died from "acute propofol intoxication," in combination with "the contributory affects of the benzodiazepines," Los Angeles County Deputy District Attorney David Walgren said.
Murray acknowledged to investigators that he gave Jackson propofol, a powerful anesthetic used for surgery, and benzodiazepines to help him sleep in the hours before his death, the prosecutor said.
Although Jackson was likely dead on arrival at the hospital, emergency room doctors continued resuscitation efforts for more than an hour, two UCLA doctors testified Thursday.
Dr. Thao Nguyen said Murray "appeared devastated" as she spoke to him in the emergency room.
"He asked me not to give up easily and try my best to save the patient," Nguyen testified.
But the doctor in charge testified Jackson was dead when the ambulance pulled up to the emergency room door at 1:13 p.m.
"The patient had no signs of life," Dr. Richelle Cooper testified.
After an hour of frantic efforts to restart Jackson's heart, the UCLA doctors made a deal with Murray, Nguyen said.
A balloon pump would be placed into Jackson's aorta in an effort to increase the oxygen supply and decrease the demands on the heart, Nguyen said.
They agreed to the last-ditch effort with the "understanding with Dr. Murray that if this should fail we will call it," Nguyen said. "Unfortunately, it did not help revive the patient."
Cooper declared Jackson dead at 2:26 p.m.
The prosecution contends that Murray misled the doctors about what might have caused Jackson to stop breathing -- information that might have helped them revive the singer.
"Dr. Murray reported the patient had been in his usual state of health, not ill, but working very hard, and he thought he may be dehydrated," Cooper said.
Both doctors said Murray told them about one benzodiazepine, Lorazepam, that he gave Jackson, but he said nothing about the propofol or other benzodiazepines he later told investigators about.
"He said that the patient had been preparing for a tour in England and had been very tired and had some difficulty sleeping and had some medications for sleep," Nguyen said.
Prosecutors presented phone records Thursday that suggest Murray was talking on his cell phone almost nonstop for the 45 minutes leading up to when he realized Jackson was not breathing.
The calls were with another patient, his Las Vegas clinic and Anding in Houston, Los Angeles Police detective Dan Myers said.