James Holmes, pictured in a Colorado courtroom, during his arraignment on March 12, has reportedly converted to Islam. Reuters

The jury in the trial of Aurora theatre shooter James Holmes unanimously agreed that the death penalty should remain an option during the sentencing portion of the trial. In the final stage of the sentencing phase of the trial, both sides will be able to make their last pleas, including testimony from victims of the massacre.

According to the Associated Press, following closing statements the jury will make its decision whether the 27-year-old mass murderer should be given the death sentence or be given life in prison. Holmes was convicted in July of killing 12 people and injuring 70 during the July 2012 shooting in Colorado.

The convicted killer's defence attempted to argue that Holmes was mentally ill and could not tell right from wrong. However, the jury ultimately rejected those claims, the AP reported.

During part one of Colorado's death sentencing process, prosecutors claimed Holmes launched a horrific and cruel attack on hundreds of innocent victims. The jury agreed and noted that the shooting was so abhorrent that the death penalty could be used.

However, Holmes's defence begged jurors to show mercy, placing the blame of the attack on mental illness, the AP reported. The defence called several people to defend Holmes's character, including former teachers, family friends, as well as his parents and sister.

Robert and Arlene Holmes, his parents, told the jury that they never suspected their son had a mental illness. Holmes's father, however, admitted that the family did not speak to Holmes in the months leading up to the attack.

To further validate their claim of mental illness, the defence called on a forensic psychiatrist, who testified that Holmes was "genetically loaded" for mental illness. Holmes's grandfather and aunt had both been hospitalised with mental illness.

Robert Holmes told the jury, "He was not a violent person. At least not until the event."

According to NBC News, Robert Holmes also told the jury he still loved his son. When asked by a defence lawyer why, he responded, "Well, he's my son and, you know, we always got along pretty well and he was actually an excellent kid."