Drugs suspected in Michael Jackson's death.

The constant use of prescription painkillers plus the financial pressures may have been contributing factors in the death of the auto-proclaimed "King of Pop" Michael Jackson.

By Mary Milliken and Laura Isensee Mary Milliken And Laura Isensee – 2 hrs 27 mins ago

LOS ANGELES (Reuters) – One day after Michael Jackson's sudden death, speculation turned to what killed the 50-year-old "King of Pop" on the cusp of a long-awaited comeback concert series.

A family attorney said on Friday he had been concerned that Jackson's use of prescription drugs for dancing-related injuries would eventually prove fatal and that the entertainer's inner circle had ignored his warnings.

A Jackson family member told celebrity website TMZ.com the singer had been given an injection of the painkiller Demerol before he went into full cardiac arrest at his rental home around midday on Thursday. TMZ soon after broke the news that Jackson had died at a Los Angeles hospital.

The Los Angeles County Coroner's office said the autopsy would begin Friday morning, but it could take six to eight weeks to determine a cause of death, which will likely have to wait for the return of toxicology tests. Those tests will determine if Jackson had any drugs, alcohol or prescription medications in his system.