Michael Jackson's personal physician didn't call for an ambulance because he didn't know the singer's address.

Dr. Conrad Murray - who was staying with the 'Thriller' singer in Los Angeles when he died last Thursday (25.06.09) - insists he tried his best to get help when he discovered the star in bed but was hampered by his unfamiliarity with the rented home.

According to the medic's lawyer, Edward Chernoff, Dr. Murray tried to call 911 but was unable to get a line out because of security restrictions on the property's phone lines. He considered using his personal mobile phone but realised he didn't know the address, and so shouted for other staff to help him.

Edward said: "We can't tell you exactly when 911 was called."

The doctor rushed through the house and found Michael's chef, who alerted his security staff, who then called for an ambulance.

While waiting for paramedics, Conrad - who has been criticised for not moving the singer's body from the bed onto the floor - continued to perform CPR on the star.

Edward added: "Dr. Murray began performing CPR for several minutes as he tried to revive him, unsuccessfully,

"With Michael still on the bed, he put one hand under Michael's back for support and was compressing with his other hand. He continued to check the pulse, and the pulse remained."

The star was then taken to hospital and pronounced dead at 2.26pm.

Despite reports that Michael was addicted to prescription drugs and had been given an injection of painkiller Demerol shortly before his death, the lawyer insists his client never administered them.

He added on US TV show 'Good Morning America': "I can state unequivocally there was no Demerol. There was no Demerol administered by Dr. Murray and no one observed him using Demerol. I am not sure there that came from. I can tell you it is false."

It has now been alleged that the doctor - who first met Michael in 2006 but became his personal physician just last month - is no longer certified by the American Board of Medical Specialties (ABMS).

The ABMS, which oversees 24 Member Boards, says Dr. Murray was certified in internal medicine by the American Board of Internal Medicine, but that certification lapsed when he didn't maintain it, and expired in December.

In addition, he has not been certified by the ABIM in cardiovascular disease.

Meanwhile, the cardiologist has made a claim to concert promoters AEG Live - who arranged Michael's 50-date 'This Is It' London residency - for $300,000 in unpaid fees.

However, according to Randy Phillips, CEO and president of AEG Live, the contract to pay Dr. Murray had not been signed by the singer before his death and so is not valid.