Deputy district attorney David Walgren holds a bottle of propofol found at Michael Jackson's residence during Dr.Conrad Murray's trial in the death of Jackson in Los Angeles October 6, 2011.[Photo/Agencies]

Dr. Conrad Murray sits at the defense table with his attorney J. Michael Flanagan (L) during his trial in the death of pop star Michael Jackson in Los Angeles October 6, 2011.[Photo/Agencies]

An attorney for Michael Jackson's in-house doctor challenged a crime scene investigator on Thursday and suggested she conducted a shoddy examination of the bedroom where the "Thriller" singer stopped breathing in 2009.

Jurors in the involuntary manslaughter trial of Dr. Conrad Murray also heard from a toxicologist, who said he found the anesthetic propofol in Jackson's blood, liver, urine and stomach. The sedative lorazepam and other medications were also found in his body.

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. Murray's attorney, Ed Chernoff, mounted the defense team's most forceful challenge since the trial began in Los Angeles on September 27.

Murray has admitted to giving Jackson propofol through an intravenous injection as a sleep aid on June 25, 2009. His attorneys say Jackson gave himself an extra, fatal dose of the drug once Murray was out of the room.

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?" Chernoff asked her.

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.

Chernoff questioned 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, Fleak said.

Prosecutors and defense attorneys agree 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.

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 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 on 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.