In Michael Jackson's body, the coroner found a deadly mix of sedatives. A cornerstone of the case against Murray is whether the singer took anything on his own when the doctor stepped away.
Last week, the defense conceded their original theory - that Jackson drank a lethal dose of the sedative propofol - was not possible.
Murray's legal team is now scrambling to deflect new evidence that appears to debunk the defense's back-up theory - that Jackson took eight pills of the sedative lorazepam, creating a toxic mix.
During cross examination of Dan Anderson of the Los Angeles County Coroner's Office, defense attorney Michael Flanagan pointed out that there were no levels tested in Jackson's stomach for lorazepam, even though lorazepam was found throughout Jackson's body.
The defense had a separate lab test gastric contents, and that lab found a higher proportion of the sedative. It was the smoking gun the defense was looking for.
In a hearing on Monday, which was held without jurors, the prosecution asserted that the defense measurement was misleading. Deputy District Attorney David Walgren said it showed amounts of lorazepam that accumulated over days - not just hours - before Jackson's death.
"The result is an artificially inflated number of the amount of drug in the stomach," Walgren said.
The prosecution called for additional testing and turned over results of the new test late Friday. The defense requested time to regroup as they review the data.
"There has to be some notes. We need to address those with our experts, we need that information and we need to review this with them," said defense attorney Ed Chernoff.
A hearing is set for Tuesday for further discussions about the new toxicology evidence. Jurors were told to call in on Tuesday afternoon to see if they should come in on Wednesday.
Court was not in session on Monday because Dr. Steven Shafer, the prosecution's last witness, had a death in his family. Shafer is considered an expert on propofol, the powerful sedative that led to Jackson's death.
The trial will soon enter a new phase as defense attorneys look to counter three weeks of damaging testimony and try to show that the singer caused his own death.
Defense attorney Nareg Gourjian told the judge on Friday that the defense will likely call 15 witness to the stand including police officers, experts and character witnesses.
Murray is on trial for involuntary manslaughter for Jackson's sudden death on June 25, 2009, at the age of 50. Prosecutors allege Murray tried to hide the fact that he had been giving propofol to Jackson.
Murray, 58, has pleaded not guilty and has denied any wrongdoing. If convicted, he could face up to four years in prison and lose his medical license.
The trial is expected to last five weeks, with Oct. 28 being the estimated last day.