Dream job turns to tragedy for Jackson doctor July 10, 2009, 5:02 PM EST LOS ANGELES (AP) -- Dr. Conrad Murray called it a once-in-a-lifetime opportunity: He signed on as Michael Jackson's personal physician in May for a six-figure monthly salary and agreed to accompany him for the entertainer's much-hyped London comeback concerts. Now, with Jackson dead, the Las Vegas cardiologist has vanished from public view and his future is unclear as police investigators unravel the details of Jackson's complicated medical history and extensive drug use. Murray hasn't spoken publicly since Jackson died June 25, leaving it to his lawyers to recount what happened when Jackson was stricken June 25 in his rented mansion. One of Murray's friends recently spoke to him and described the normally upbeat, easygoing doctor as shaken. "Anything like that, I'm sure it's going to weigh heavy on you," said retired autoworker Ben Mask of Houston, 69, who is also a patient of Murray's. With Murray out of sight, his role in Jackson's final weeks and days remains murky. Authorities are awaiting toxicology results and other tests being conducted by the coroner to determine a cause of death. The singer's family requested a private autopsy in part because of questions about Murray's role, the Rev. Jesse Jackson has said. Among other things, Murray's lawyers have acknowledged it took up to 30 minutes for paramedics to be summoned to Jackson's home after he was found unresponsive and Murray began CPR. Murray declined an interview request through his lawyer's office. His lawyers say that although his car was impounded by investigators, he is not a suspect, and police credit the doctor with providing helpful information during a three-hour interview. "Dr. Murray didn't prescribe or administer anything that should have killed Michael Jackson," one of his attorneys, Edward Chernoff, said in a statement. Murray, 56, first met Jackson in Las Vegas when the doctor treated one of the singer's children a few years ago. Why a cardiologist treated a child or why Jackson wanted a heart doctor by his side remain unclear, but he became the pop star's personal physician in May.