A witness took the stand on Thursday Oct. 13, testifying that Michael Jackson's reliance on the painkiller Demerol could have led to insomnia, which Murray was trying to treat.

Dr. Nader Kamangar, a sleep medicine expert, said that he found the pop icon had received Demerol from dermatologist Dr. Arnold Klein, when he reviewed Jackson's records.

I usually avoid using Demerol on patients, Kamangar testified. It can actually activate someone, make them more hyper or excited, create more stimulation.

However, Kamangar claimed that he didn't confirm that if Jackson had a Demerol dependency. He also maintained that even if the King of Pop addicted to Demerol which caused by others, Murray still made egregious mistake in giving Jackson propofol without properly monitoring him, according to Reuters.

Mr. Jackson was receiving very inappropriate therapy in the home setting, receiving very potent sedatives including propofol, midazolam and lorazepam without appropriate monitoring by Dr. Murray, and ultimately this cocktail was a recipe for disaster in a patient that had underlying dehydration, Kamangar told the court.

This isn't the first time that the witnesses criticized Murray because he gave the singer propofol recklessly at Jackson's home where there no enough paramedic or monitoring equipment.

Meanwhile, the defense tried to prove that Jackson was addicted to the drug and Murray was only trying to help the star solve the addiction problem caused by other doctors.

Defense attorney Ed Chernoff even said in the opening arguments that several months before the singer died, he had often visited Klein's office, even twice or three times a week. Dr Arnold Klein addicted Michael Jackson to Demerol, Chernoff said.

But Judge Michael Pastor has denied a defense request to call Klein as a witness, ruling his testimony would be insufficiently relevant.

On Thursday, prosecutors said they were almost close to wrapping up their witnesses, which are over 30. The last witness is an expert on propofol Dr. Steven Shafer, who will testify on Monday. The defense plans to call 22 witnesses to the trial.

The trial is scheduled to last about four weeks. If convicted, Murray could serve a sentence of up to four years in prison and also lose his medical license.