The defence case for Dr Conrad Murray – the physician charged with involuntary manslaughter over the death of pop great Michael Jackson – will argue that the “Thriller” star administered his own fatal overdose.

Murray has pleaded not guilty to criminal charges over the 50-year-old’s death back in June 2009. Jackson’s estranged father, Joe, announced last week that he’s also planning to launch a civil lawsuit against the doctor for wrongful death. According to celebrity site TMZ.com, lawyers for Murray will tell the courtroom that Jackson accidentally gave himself a fatal dose of the powerful drug Propofol on the night of his death, administering the drug after waking up alone two minutes after Murray had left his bedroom.

The dose led the singer to go into cardiac arrest. Lawyerswill claim Murray only administered a small dose of the drug – 25 milligrams, and then stayed with him for an hour while making phone calls. They will also argue that the pop icon was a long-time Propofol addict, and that Murray returned to the room, saw what Jackson had done, and called immediately for help.

“Los Angeles County Coroner’s investigators took a picture in the room, showing an empty Propofol bottle on the floor, underneath the nightstand by Jackson’s bed,” says the website. “The defence will argue Jackson grabbed the bottle from the nightstand, injected himself and then dropped the bottle.”

Last week former bodyguard Alberto Alvarez claimed Murray stopped CPR to hide bottles of the drug. Claims over the website’s allegations are yet to be commented by either party’s legal team.