LOS ANGELES (AP) - For several moments, the milky white substance that authorities say killed Michael Jackson dripped down into an IV line a few feet away from jurors.
Sometimes the drops fell fast, until their rate was slowed by the Columbia University researcher and professor who for three days has testified about the drug and its effects on the King of Pop as he died. The demonstration, with the anesthetic propofol dripping harmlessly into a water bottle, was one of the final scenes prosecutors presented Thursday to jurors hearing the involuntary manslaughter trial of Dr. Conrad Murray.
On Friday, Murray's lead attorney will finally get his chance to question the expertise and assumptions laid out by Dr. Steven Shafer, the prosecution's final and one of its most important witnesses. The Houston-based cardiologist has pleaded not guilty.
After days of testimony and demonstrating the type of IV drip that was likely present in Jackson's bedroom in his final hours, Shafer bluntly responded to a question about Murray's culpability.
"He has been entrusted by Michael Jackson to look after his safety every night and he has failed," Shafer said.
Sitting in the courtroom, watching and listening to it all was Shafer's former teacher and longtime colleague, Dr. Paul White, who will testify for the defense.
Shafer opened Thursday's testimony by saying he was "disappointed" in his former instructor, who earlier this year had written in a report that he thought it was possible Jackson had died after swallowing a dose of propofol.
Shafer told jurors that medical studies dating back to 1985, performed on animals as varied as rats, dogs, monkeys and more recently, humans, had shown that propofol if swallowed wouldn't produce sedation or any ill effects.
White has been taking notes throughout Shafer's testimony and his observations will likely influence lead defense attorney Ed Chernoff when he begins his cross-examination Friday afternoon.
Shafer also attempted to discredit another defense theory - that Jackson may have swallowed eight lorazepam pills in the hours before his death without Murray's knowledge and that authorities overlooked it. He said the amount of lorazepam that was found in Jackson's stomach was "trivial."
The only explanation that supported all the evidence - including the items found in Jackson's bedroom, the singer's autopsy results and Murray's lengthy statement to police - is that Murray gave the singer propofol on an IV drip and left the room when he thought the singer was safely asleep.
"This fits all of the data in this case and I am not aware of a single piece of data that is inconsistent with this explanation," Shafer said.
Using charts and his own experience, Shafer said that Jackson likely stopped breathing because of the propofol and without someone to clear his airway. The whole time, propofol would have kept dripping into the IV tube, gravity carrying it into the singer's body.
In all, Shafer said Murray committed 17 violations of the standard of care that could have led to Jackson's serious injury or death.
Murray's actions in setting up the IV stand in Jackson's bedroom - similar to the one Shafer set up in front of the jury box Thursday - led to the singer's demise and his Murray alone was to blame, Shafer said.
"He is responsible for every drop of propofol in that room, every drop of lorazepam in that room," Shafer said.
AP Special Correspondent Linda Deutsch contributed to this report.