Jackson doctor's defense looms in trial's 4th week

By ANTHONY McCARTNEY | October 19, 2011 | 10:26 AM EDT

Dr. Conrad Murray looks behind during his involuntary manslaughter trial, Thursday, Oct. 13, 2011, in downtown Los Angeles. 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. (AP Photo/Robyn Beck, Pool)

LOS ANGELES (AP) — The trial of Michael Jackson's doctor will soon enter a new phase as attorneys for Conrad Murray look to counter three weeks of damaging testimony and try to show that the singer caused his own death.

Murray's lawyers have told jurors that his involuntary manslaughter case will hinge on the science of what killed Jackson.

They will call their own experts to counter prosecution witnesses who have repeatedly told the jury that Murray was reckless when he gave Jackson a powerful anesthetic to help him sleep.

It's not clear when the defense will begin to present its case, however. Monday testimony has been canceled because prosecution witness Dr. Steven Shafer will be unavailable.

Court spokeswoman Mary Hearn said Sunday the trial's resumption will be announced when more information is available.