Holmes' trial had been set to begin Oct. 14. But the psychiatrist conducting a second examination, one requested by the prosecution, asked for a two-month extension of his deadline from Aug. 15 to Oct. 15, Superior Court Judge Carlos Samour said. He scheduled a hearing July 21 to discuss a new trial date.
"The court recognizes that most of the named victims likely oppose a postponement of the trial date," Samour wrote. "However, the court has little choice but to grant the examiner's request. As the court has observed before, this is a complicated and voluminous case, and it is important that the second examination is adequate and complete."
Holmes, a former graduate student in neuroscience at the University of Colorado, allegedly killed 12 people and injured many more in a shooting spree in a movie theater in Aurora, Colo. The massacre occurred during a midnight showing of The Dark Knight Rises in July 2012.
Prosecutors plan to seek the death penalty if Holmes is convicted. His lawyers are preparing for an insanity defense.
The trial was originally set to begin last August. It was delayed once by prosecutors' decision on the death penalty and a second time by their request for another psychiatric evaluation.