Feature: Colorado theater shooter's little sister sobs in court defending brother

James Holmes' 22-year-old sister broke down in tears repeatedly on the witness stand Monday defending her big brother, who methodically planned and executed one of the worst mass murders in U.S. history.

Chris Holmes told the jury, who found her brother guilty of all 165 counts against him two weeks ago, that he had changed dramatically, and should not be given a death sentence.

Chris said she would never describe her brother as mean-spirited or selfish.

"He never wanted to be the center of attention, and he liked to keep how he was feeling to himself," she said. "He didn't want burden others...he was always looking out for my Mom," she said, tearfully.

With only days left in the defense's best chance go spare Holmes from a death penalty conviction, the first Holmes family member took the stand to defend the convicted.

If this emotional testimony is enough to convince one of the 12 jurors, then Holmes, who killed 12 and injured 70 others by gunfire at a Batman movie three years ago, will avoid execution and spend the rest of his life in jail.

The jurors are expected to vote on this key component of the trial -- "mitigating factors," such as Holmes's mental illness -- by the end of the week.

If the jurors decide that Holmes' terrible mental illness outweighs the premeditated murders he committed showing "extreme indifference," then the trial will end immediately and Holmes will be sentenced to life in prison.

However, if the jurors say "aggravating factors" such as Holmes' careful planning to maximize casualties in the 2012 attack outweigh the defenses' attempt to humanize Holmes, then a death sentence is likely.

As an added twist, the Holmes defense team Monday produced the key psychiatrist who testified three months ago that Holmes was sane at the time of the attack and helped sway the jury to reject Holmes' "not guilt by reason of insanity" plea.

Dr. Jeffrey Metzger framed a solid argument supporting Holmes' extreme psychosis -- a condition that could easily put "doubt" in the mind of one juror to find "mercy."

Meanwhile, Metzner, who testified Holmes knew right from wrong, also told jurors Monday the attack never would have happened if not for Holmes' mental illness.

"(Holmes) acted on his delusions, and that's a reflection of the severity of his mental illness," Metzner said.

Metzner said Holmes suffers from schizoaffective disorder and his actions were directly related to delusions that killing people would increase his self-worth.

It is likely that Holmes' mother Arlene will take the stand in the next two days for riveting testimony that will be the defense's last-ditch attempt for their client to avoid a verdict of death. Endi