Michael Jackson's jab dabs are not those of Dr Conrad Murray

Mystery fingerprints on the syringe that killed Michael Jackson are not those of Dr Conrad Murray or any member of Jacko's family or staff, the investigation has found.

The fingerprints point to an intruder murdering the superstar.

"A jury cannot convict," The Sun quoted a source of the medic's looming trial for involuntary manslaughter as saying.

"Murray and Michael were the only ones supposedly at the house at the time, but the prints point to someone else using the fatal syringe.

The doctor's jubilant legal team will insist to jurors: "If the print doesn't fit, you must acquit," the source added.

Murray said it backs his theory a robber crept into the Los Angeles home of the 'Thriller' star and swiped a million dollars.