Centennial - When the younger sister of Colorado theatre shooter James Holmes visited him in jail nearly two years after the attack, his eyes bulged from his head and he spoke in short, stilted phrases, a vast difference from the loving brother who protected her while they were growing up, she testified on Monday.Chris Holmes, aged 22, became the first in her family to testify at her older brother's death penalty trial on Monday, saying in an effort to spare his life that she did not believe her brother was mentally ill growing up, but she also did not know how to recognise the signs."His whole demeanour seemed different," she said, fighting tears as she described the May 2014 jail visit. "He seemed emotionally uncomfortable" and gave one-word answers, but "we were happy to see each other".Jurors are considering whether James Holmes should serve life in prison without parole or be executed for killing 12 people and injuring 70 others in a crowded movie theatre on July 2012. Defence attorneys say he should get a life term because he is severely mentally ill.Jurors saw the siblings smiling together in family vacation photos as Chris Holmes described their unremarkable childhood. There were photos of them riding bikes as kids and wearing Santa hats at Christmas time, smiling.Tearful testimony"There was a time when we were happy," she said.But she said her brother had a hard time finding friends and adjusting when they moved from the California city of Salinas south to San Diego. He was an introvert who kept his feelings to himself for fear of burdening others, she said.Holmes had no visible reaction to his sister's sometimes tearful testimony, even as she sat just feet from the defence table where he was tethered to the floor.Earlier on Monday, a court-appointed psychiatrist who found Holmes was legally sane during the attack testified that his severe mental illness led him to open fire on the theatre.Dr Jeffrey Metzner's finding has not changed: He concluded that Holmes knew right from wrong, therefore meeting the legal definition of sanity under Colorado law. But Metzner also said the attack would not have happened if not for Holmes' mental illness."Having psychosis doesn't take away your capacity to make choices. It may increase your capacity to make bad choices," Metzner testified. "He acted on his delusions, and that's a reflection of the severity of his mental illness."Metzner, who diagnosed Holmes with schizoaffective disorder, said he did not think Holmes went on his rampage to get notoriety or because of his longstanding hatred of mankind, which he described in a spiral notebook.Instead, Metzner said, Holmes' actions were "directly related" to delusions that killing people would increase his self-worth."I can come up with no other explanation for what he did," Metzner said.Mentally illJurors rejected Holmes' insanity plea and convicted him of 165 counts of murder, attempted murder and other crimes.They decided unanimously last week that the attack was cruel enough to justify the death penalty, but they must now determine whether Holmes is so mentally ill he should not be executed.Also on Monday, Holmes' lawyers asked the judge to question a dozen jurors who said they heard about the deadly theatre shooting last week in Lafayette, Louisiana. The defence feared some jurors might decide Holmes should be sentenced to death for possibly inspiring a copycat shooting.Judge Carlos A Samour determined that they had learned little about the shooting on Thursday that killed two and wounded nine others and could still be impartial.