Sade Anding testified that Murray called her at 11:51 am on June 25, 2009, when she was in Houston and he was at Jackson's rented mansion, trying to help the star get to sleep.
About five or six minutes into the conversation she realized that Murray was no longer answering, and the sound became muffled, as if the telephone was in a pocket.
"I said 'Hello, Hello,' and I didn't hear anything. I pressed the phone to my ear," she told the LA Superior Court. "I heard mumbling of voices and I heard coughing," she added.
She listened to the muffled noises for about three to four minutes before hanging up, she said, adding that she tried twice to call him back, but got no answer.
Murray is accused of involuntary manslaughter over the singer's death, allegedly by administering an overdose of the powerful sedative propofol while trying to help Jackson with his insomnia.
The trial has already heard from paramedics who arrived at Jackson's Holmby Hills mansion at 12:26 pm after receiving a 911 call at 12:21 pm - about 20 minutes after the mysteriously-ended phone call with Anding. (AFP)