Anesthesiology expert Dr. Steven Shafer holds an intravenous line as he is cross examined by Ed Chernoff, a defense attorney for Dr. Conrad Murray during Murray's involuntary manslaughter trial in Los Angeles
Anesthesiology expert Dr. Steven Shafer holds an intravenous line as he is cross examined by Ed Chernoff, a defense attorney for Dr. Conrad Murray during Murray's involuntary manslaughter trial in Los Angeles October 21, 2011. Murray has pleaded not guilty and faces four years in prison and the loss of his medical license if convicted of involuntary manslaughter in Michael Jackson's death. Reuters

An attorney for Michael Jackson's doctor counterattacked the demonstration of IV drip system for jurors on Friday, Oct. 21, for the type of IV line used in the demonstration was never found at Jackson's house.

The courtroom demonstration, suggesting that Dr. Conrad Murray could have given Jackson a deadly anesthetic propofol infusion by an IV drip, was made by Dr. Steve Shafer, a top expert in the anesthetic propofol, a professor at Columbia University.

Ed Chernoff, the lead attorney for defendant Murray at his involuntary manslaughter trial in Jackson's 2009 death, claimed during cross-examination Shafer had drawn conclusions without enough evidences.

You certainly do consider that what you have claimed occurred in this case is an extraordinary claim? Ed Chernoff asked Shafer on the witness stand.

Not at all, Shafer said.

Shafer said Murray could have used a vented IV tube with a plastic spike which was used in the demonstration and took away the tube before leaving Jackson's house.

On the same day, Los Angeles Superior Court Judge Michael Pastor set a Nov. 16 hearing outside the presence of jurors to determine whether he should find Dr. Paul White, who called either Shafer or Deputy District Attorney David Walgren a scumbag during the courtroom demonstration on Thursday.

White denied saying so, but he admitted that he told Walgren it was inappropriate to tamper with evidence found at the scene.

CTV news stated that White and Shafer have known each other for nearly 30 years. Reuters quoted Shafer that he considers White a friend, but their friendship seems to be tested by the Murray trial.

As a defense expert, White will take the witness stand next week, and defendant will present their cases from then on.

Murray admitted in his previous testimony that he gave propofol to help Jackson to sleep on the day of his death, though however, it's only a small quantity of the drug, which never threatened Jackson's life. Actually Jackson regarded the drug as milk and took the lethal dose by himself, which led to his sudden death.

If convicted, Murray could face a maximum sentence of four years in prison and the loss of his medical license.