Dr. Murray's Girlfriend Subpoenaed to Testify Before Grand Jury

The girlfriend of Michael Jackson's former personal doctor has been ordered to appear Wednesday before a grand jury in Los Angeles, according to a subpoena obtained by ABC News.

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Nicole Alvarez, the girlfriend of Dr. Conrad Murray, who remains the focus of a manslaughter investigation into the pop star's death, has been called as a witness "in an investigation pending before said grand jury," according to the subpoena. Jackson's June 25 death was ruled a homicide caused by drugs administered in Jackson's mansion by Murray, his personal physician.

VIDEO: Dr. Conrad Murray admits giving Micheal Jackson several drugs before he died..Play

A spokeswoman from the Los Angeles District Attorney's office declined to comment to ABC News about the subpoena but a law enforcement source confirmed that this subpoena is for an "investigative grand jury."

Alvarez is cooperating with law enforcement, said Joseph Low, her attorney. Low told ABC that the court refused to give him any information about what case Alvarez is supposed to testify about and what subjects might be covered. The court also refused to verify that the subpoena is even legitimate, given that it was unsigned and undated. "It's not usual for lawyers to have this much trouble getting information," he said. "They told me my client should just show up." A search warrant obtained by ABC News states that on August 13, 2009 police looked in Alvarez's home and a car registered to Murray's sister and retrieved a business card with Conrad Murray's name on it, a piece of paper, a receipt and a medical invoice.

VIDEO: Warrant says lethal levels of propofol killed Michael JacksonPlay

Alvarez, who reportedly gave birth in March to Murray's seventh child, a baby boy they named Che Giovanni, is a resident of Santa Monica, Calif. She has reportedly been Murray's girlfriend since 2005 but is not clear from the documents how she plays into the manslaughter investigation into Murray.

It has been almost three months since Michael Jackson's death on June 25. While no charges have been filed in the case a manslaughter investigation is continuing and a preliminary report released by the coroner last month determined that the singer's death was caused by a lethal combination of prescription drugs.

The Los Angeles County Coroner's office released a statement saying the late King of Pop died because of acute propofol intoxication. The office cited benzodiazepine effect as another condition contributing to his death.

Propofol and lorazepam were cited as the primary drugs responsible for Jackson's death. The statement noted that other drugs detected in his system were Midazolam, Diazepam, Lidocaine and Ephedrine.

The coroner ruled the manner of death a homicide.

The coroner's announcement follows search warrants showing that police found marijuana and numerous empty drug bottles at Jackson's home shortly after he died.

Two bags of marijuana, a bottle of the drug temazepam, which is used to treat sleeplessness, empty bottles of the sedatives lorzaepam and diazepam were discovered during the search. Police also uncovered four more empty pill bottles with no sign of what they may have contained.

The warrants, which were served on June 29, also say that the day Jackson died, while investigators were at the house, "family members of the decedent notified Los Angeles County Coroner's Assistant Chief Ed Winter that they had located a quantity of tar heroin in [Jackson's] bedroom on the second floor of the residence. Winter notified LAPD detectives of the found evidence." The warrant fails to mention if the evidence really turned out to be heroin.

Another search warrant revealed that on the morning of his death, Jackson had "lethal levels" of the powerful anesthetic propofol in his blood.

According to the warrant,Jackson received a cocktail of painkillers and sedatives including the powerful anesthetic propofol.

Murray told investigators he had been treating Jackson for several weeks and had been trying to wean the singer off propofol by administering a series of prescription sedatives including lorazepam and midazolam.

Commenting on the affidavit released Aug. 24, Edward Chernoff, Murray's attorney, said, "Much of what was in the search warrant affidavit is factual. However, unfortunately, much is police theory. Most egregiously, the timeline reported by law enforcement was not obtained through interviews with Dr. Murray, as was implied by the affidavit.

"Dr. Murray simply never told investigators that he found Michael Jackson at 11:00 a.m. not breathing. He also never said that he waited a mere 10 minutes before leaving to make several phone calls. In fact, Dr. Murray never said that he left Michael Jackson's room to make phone calls at all."

Murray told investigators previously that Jackson had developed an addiction to the 50mg of propofol he received through an IV every night, demanding the hospital-grade anesthetic he called his "milk."

On June 23, Murray said he successfully put Jackson to sleep without using propofol. At 1:30 a.m. on the morning of June 25, the day Jackson died, Murray gave the singer Valium. At 2 a.m. Murray gave the singer 2mg of lorazepam through an IV.

At 3 a.m., singer Murray gave Jackson midazolan, followed by another 2mg of lorazopan at 5 a.m. when the singer still could not sleep.

At 7:30 a.m., he gave him an additional 2mg ofmidazolan. Murray told investigators he was at Jackson's bedside the whole time monitoring the singer with a pulse oximeter.

At 10:40 a.m., when Jackson still could not fall asleep and after "repeated demands/requests from Jackson," Murray gave him 25mg of propofol diluted with painkiller lidocaine.

Murray told investigators he left the room for 10 minutes to use the bathroom and when he returned Jackson was not breathing. The doctor then initiated CPR.

Murray had assistant Alberto Alvarez call 911 and asked Jackson's chef to send for the singer's oldest son Prince, 12.

"Murray's cellular telephone records show Murray on the telephone with three separate callers for approximately 47 minutes starting at 11:18 [a.m.] until 12:05 [p.m.,]" the affidavit stated.

Paramedics arrived on the scene around 12:22 p.m.

The warrant was issued in Texas in July when Murray's offices there and in Las Vegas were raided by local police and federal authorities investigating Jackson's death.

"The Jackson family has full confidence in the legal process, and commends the ongoing efforts of the L.A. County Coroner, the L.A. District Attorney and the L.A. Police Department. The family looks forward to the day that justice can be served," the family said in a statement following the release of the warrant.

Investigation of Conrad Murray

Murray remains the focus of a manslaughter investigation. The final results of the autopsy have not been released.

"I have told the truth and the truth will prevail," Murray last week in his first public statement since Jackson died on June 25.

In a video statement posted to YouTube, Murray thanked his friends and patients for their letters and messages of support.

"I want to thank all of my patients and friends who have sent such kind e-mails, letters and messages to let me know of your support and prayers for me and my family. Because of all that is going on, I am afraid to return phone calls or use my e-mail. Therefore I recorded this video to let all of you know that I have been receiving your messages. I have not been able to thank you personally, which as you know is not normal for me. Your messages give me strength and courage and keep me going. They mean the world to me," he said.

"Please don't worry, as long as I keep God in my heart and you in my life I will be fine. I have done all I could do. I told the truth and I have faith the truth will prevail. God bless you and thank you," he said in the one-minute video.

The Los Angeles County coroner has completed its autopsy and toxicology, but is holding the its findings until the police complete their investigation. Speculation is mounting that Murray will be charged with manslaughter.

Investigators found numerous vials and pills bottles in Jackson's home and in Murray's offices.

The Texas-based cardiologist has a record of disciplinary actions taken against him.