The courtroom where the Colorado theater shooting trial is unfolding is awash with emotion.

But the man tethered to the floor at the defense table barely moves as witnesses share details of his carnage.

Interpretations of James Holmes' stone-faced, nearly catatonic demeanor cuts to the heart of the case.

His attorneys say he seems aloof because of anti-psychotic medications he has taken since he killed 12 people and injured 70 more in the packed movie theater.

Prosecutors hint of something dark and calculating below that emotionless exterior.

The California native is so impassive that, even before his trial began, defense attorney Tamara Brady asked prospective jurors if they would read anything into his appearance.