Authorities have ruled that Jackson died of acute propofol intoxication, combined with the sedative lorazepam.
But the day's most confrontational exchange came during the testimony of coroner's investigator Elissa Fleak when Dr Murray's lawyer, Ed Chernoff, mounted the defence team's most forceful challenge since the trial began in Los Angeles Sept. 27.
Dr Murray has admitted to giving Jackson propofol through an intravenous injection as a sleep aid on June 25, 2009. His lawyers say Jackson gave himself an extra, fatal dose of the drug once Dr Murray was out of the room.
Ms Fleak combed through Jackson's bedroom with police after the singer's death.
"Would you agree with me that you made a substantial number of mistakes in your investigation?'' Mr Chernoff asked her.
Ms Fleak denied that suggestion, but acknowledged her original hand-written notes were destroyed when they were transferred into an official report. "I do that in all my cases,'' she added.
Mr Chernoff questioned Ms Fleak on her assertion that a bottle of propofol was found inside an IV bag.
Investigators found the propofol bottle and IV bag stashed inside a shopping bag in a closet area four days after Jackson's death, Ms Fleak said.
Prosecutors and defence lawyers agree that Dr Murray's fingerprint was on the propofol bottle. They also stated that Jackson's fingerprints could not be found on vials of propofol and other drugs retrieved from the bedroom and nearby.
Ms Fleak admitted her original notes did not mention finding the propofol bottle inside the IV bag, and that the first time she placed that in her notes was earlier this year.
But she denied suggestions by Mr Chernoff she had changed her findings to make them fit in with another witness. "I've never talked to prosecutors about another witness,'' she said.
In one of the odder moments, prosecutors Thursday also showed jurors a photo of a toy doll, that appeared to be made of porcelain or plastic, and was found on the bed where Jackson was found lying lifeless.