Police say they will question Michael Jackson’s cardiologist about whether drugs were to blame for the star’s death, after 911 tapes released Friday afternoon revealed the doctor was present at the time of Jackson’s collapse. Dr. Conrad Murray, who briefly disappeared Thursday after the singer was pronounced dead, was hired months ago to treat Jackson ahead of his upcoming tour. Investigators later briefly interviewed Murray and towed a car registered to Murray’s sister near Jackson’s home in the hopes that it may contain medication or other clues. LAPD Officer Robert French stressed that Murray is not the target of a criminal investigation, but said he may provide important information before Jackson’s toxicology results are returned. Jackson’s addiction to prescription drugs has led to suspicions about whether they were to blame for his untimely death.