Investigators from the Los Angeles County Coroner questioned Dr. Arnold Klein, Michael Jackson's longtime dermatologist, and subpoenaed medical records from his office as part of their investigation into the singer's death.
Jackson was a patient of Klein for two decades and the doctor's name has reportedly surfaced on a shortlist of five personal physicians authorities have sought to question.
Seen exiting Klein's office with the doctor and his lawyer, Assistant Chief Coroner Ed Winter would not name other doctors his office is questioning.
"We are not investigating the doctors -- we are investigating the death of Michael Jackson and we are contacting all of his doctors," he told reporters outside Klein's office.
Klein's lawyer dispelled rumors that the doctor had been less than forthcoming with authorities, and told reporters that his client was cooperating with the investigation.
"Dr. Klein has been and is continuing to cooperate with Mr. Winter's office and their investigation into the death of Michael Jackson," said the doctor's attorney Bradley Boyer.
Under California law, the coroner has a right to issue demands for records to determine the manner and cause of death in cases under their jurisdiction, Chief Coroner Investigator Ed Harvey told ABC News.
Jackson and Klein's relationship extended outside the walls of the exam room. The two men were friends and it was in Klein's office that Jackson met Debbie Rowe, the nurse with whom the singer had two children in the late 1990s.
Klein has been rumored to have donated the sperm with which Rowe became pregnant, an accusation the doctor has denied -- with reservations.
On July 8, he told "Good Morning America" that he was not the father of Jackson's two oldest children, Prince, 12, and Paris, 11, as he far as he knew.
"To the best of my knowledge, I am not the father of these children," he told GMA.
Klein has also denied that he prescribed Jackson any of the powerful sedatives; authorities confirmed were in his home at the time of the singer's death.
On GMA Klein denied supplying Jackson with OxyContin and Demerol, drugs the singer was said to be addicted to.
He accused doctors who prescribed addictive drugs for the pop icon of being "criminals."
"I say that anyone who makes someone an addict or gives a person potentially dangerous substances directly to them to use, like propofol is a criminal," Klein told "GMA," in reference to a powerful anesthetic Jackson is believed to have taken prior to his death.
"It becomes nothing more than manslaughter or something worse than that," he said.
Propofol, known by the trade name Diprivan, was among the drugs removed from Jackson's rented mansion, according to ABC News sources.
Meanwhile, federal drug-enforcement authorities contacted the makers of Diprivan as part of their investigation into Jackson's death, according to the Associated Press.
"He was not in terrible pain when I saw him. He danced in the office, and he danced for my patients," Klein said. "He was very muscular, and he was very, very happy and dancing." "I saw nothing at that point that would make me worry whatsoever," he continued. "But I was always concerned about him because I was always worried about other doctors."
Klein was not the doctor in Jackson's Los Angeles rental home, when he died on June 25. That physician, Dr. Conrad Murray, is also being questioned by the authorities.
The coroner has yet to supply an official cause of death for Jackson, pending the results of a toxicology screening.
ABC News' Lisa Fletcher contributed to this report.