Lawyers for James Holmes, the man who faces a death penalty trial for the Colorado Movie theatre massacre last July have announced that Holmes will plead "Not Guilty by Reasons of Insanity."

It is unknown at this time if the judge in the case, Judge Carlos A. Samour will determine if there is “good cause” as to whether Holmes can enter an insanity plea. That will be argued by defense and prosecutors at a May 13th hearing when the defense formally asks for the change of plea.

In March, the prosecutors in the case rejected the defense’s offer of life in prison with no possiblity of parole, the agreement would have spared Holmes the death penalty. In April, the prosecutors announced that they would seek death in the case.

A notebook that Holmes kept notes in that he mailed to his psychiatrist, Dr. Lynne Fenton, who was treating him prior to the massacre and intercepted by police will become evidence in the case if Holmes is allowed the insanity plea. Prior to the plea, patient-doctor confidentiality came into play keeping the notebook out of bounds. But with an insanity plea, that confidentiality will be automatically waived.

In an affidavit, Police Sgt Matthew Fyles of Aurora said the contents of that notebook “may assist in determining what methods of planning were involved to carry out the crime.”

Under Colorado law, Holmes may have to submit to truth serum during his evaluation.

If the plea is accepted, Holmes will also have to undergo a psychiatric evaluation that could potentially delay the trial which is slated to begin in February of 2014.

Holmes killed 12 and wounded another 70 when he went on a killing rampage in a theatre in Aurora, Colorado last summer. He faces 166 counts that include murder and attempted murder.