Witness Struggled To ID Colorado Cinema Killer

A witness at the US trial of alleged cinema killer James Holmes struggled to identify him when asked to do so by the defence team in court.

Jose Sanchez-Lopez instead pointed to a juror until Holmes' lawyer Rebekka Higgs laughed and asked him if he was nervous.

Higgs directed his attention to the defence table and Sanchez-Lopez admitted he was.

The witness then went on to describe encounters with Holmes during his shifts at a company that made vitamin tablets.

He said the defendant did not seem to understand when co-workers were joking with him.

During one "episode", Sanchez-Lopez said he saw Holmes staring at the wall.

"He looked spaced out," Sanchez-Lopez said. "He was staring at it like someone was talking to him."

Holmes had a "smirk" on his face, the witness said.

Sanchez-Lopez had never seen Holmes do that before. When he asked Holmes if he was OK, Holmes did not respond. "It was like I wasn't there," he said.

The 27-year-old man is accused of carrying out 12 murders and injuring 70 other people during a shooting attack at a midnight premiere of a Batman film in a cinema in Aurora, Colorado in July 2012.

Holmes, a former neuroscience student, has pleaded not guilty by reason of insanity.

His legal team has said the defence case could take up to two weeks to complete.

The trial continues.