He spoke of his son's idyllic boyhood in Castroville, a small California town south of San Jose that treasured its children. He described the social awkwardness and isolation that came with a move at 12 to a bigger city, San Diego. The boy once surrounded by a pack of friends suddenly had no one.
But he still had soccer, and he still had school. "He still had a family that loved him," the elder Holmes testified.
He looks back now at that move as a pivotal time in his son's life. There was a before and an after. Before is the Oak Hills neighborhood, near Monterey. After is San Diego.
"He was happiest when he was playing soccer when he was a young kid," Robert Holmes testified. "Oak Hills was probably the happiest time in his life -- and ours, too."
In court, Holmes tried with mixed success to connect with his son. He'd spent most of the lengthy trial sitting a few feet behind James. Now, he was on the witness stand, directly in front of him.
Robert Holmes smiled during sidebar conferences. He raised his eyebrows. He mouthed the word "hello."
But, as he has throughout his trial, James Holmes simply rocked softly in his chair at the defense table. It was impossible to see from the spectator's section whether his father succeeded in making eye contact, but his repeated attempts suggest not.
James Holmes does not interact with the people around him at his trial. He doesn't talk to his lawyers, and they don't talk to him. At times, they talk over him as he sits there, rocking.
After he received a few visits, he now refuses to let his parents visit him in jail.
A family history of mental illness
His father's testimony revealed a longer, wider disconnect. As Holmes got sicker, he pushed his family away. His mother and father didn't have a clue.
Despite a family history of mental illness, it was something that wasn't talked about.
Robert Holmes referred in his testimony to "two breakdowns" his twin sister suffered but said he never learned the diagnosis. His own father suffered from some sort of mental illness in his later years, Holmes testified, but he didn't know what it was.
"Our family didn't discuss it," he said.
James Holmes never told his parents about the intrusive homicidal and suicidal thoughts he has said plagued him since 15.
"His mental illness was disturbing to him," testified Jeffrey Metzner, a court-appointed forensic psychiatrist.
His parents never knew he was mentally ill, although they began to suspect something was wrong when he visited them at Christmas in 2011. He was pale, scrawny and worn down.
At one point, his father noticed an odd, wide-eyed, faraway expression. Months later he'd see that look again -- in his son's mug shot.
James Holmes was diagnosed that Christmas with mononucleosis and spent the holiday break sleeping and playing video games. When he returned to school, he avoided calls and emails from both his mother and father.
Worries of where James was headed
They learned in June that James was seeing a psychiatrist. The family had been to counselors before. But this time they were worried because the psychiatrist said James, who had broken up with the only girlfriend he'd ever had, planned to drop out of school.
The parents began to research what might be wrong and came up with a theory -- Asperger's syndrome. They left a voicemail with the psychiatrist, Dr. Lynne Fenton, but she never called back. His father thought James might be depressed.
"If Dr. Fenton had told you how sick your son was, would you have done something to try to help him?" defense attorney Tamara Brady asked. But prosecutor George Brauchler objected, and Holmes was not permitted to answer.
Holmes was making plans to take off work and visit his son in Colorado when the phone rang in the middle of the night. It was someone from the media. There had been a shooting, the caller said.
At first, he testified, he thought Jimmy had been shot.
No, he was told, his son was the shooter.
By now, the horrific facts are well-known.
That night in Aurora
On July 20, 2012, James Holmes donned a helmet and ballistic gear, packed 700 rounds of ammunition and three guns into his car, and drove to a movie theater in suburban Aurora, Colorado
. He tossed a tear gas canister into the front seats and opened fire, killing 12 and wounding 70 in one of the worst mass shootings in recent U.S. history.
He has been convicted of 24 counts of capital murder, and prosecutors are seeking the death penalty. They proved four factors that make his crime deserving of the ultimate punishment -- including exceptionally cruel, multiple murders and ambushing the victims.
The jury rejected Holmes' insanity defense. But there's no dispute that he was seriously mentally ill, suffering from some form of schizophrenia, according to expert testimony.
This is the so-called mitigation phase of the trial. It is up to the defense to raise reasons why Holmes shouldn't be executed. The defense is hoping that mental illness -- and the fact people still love Holmes, at least the boy they knew -- could be reason enough to spare him from the ultimate punishment.
More than two dozen witnesses have testified, painting a vivid picture of Holmes' family life. Unlike many people on death row, Holmes childhood seemed almost idyllic.
"Jimmy was always really an excellent kid," his father testified.
Friends, neighbors, schoolmates and teachers agreed, describing a smart, sweet, exceptional boy.
"A Renaissance child," his fifth grade teacher called him.
The witnesses also spoke of doting parents who did everything they could to raise happy, successful children. Dozens of photos were shown of an adorable baby, a grinning boy, a loving brother, and an awkward teen and young adult. Other photos and videos showed the parents snuggled in a huge bed with their two children, family camping trips and vacations, ball games, summer and winter trips to the mountains, beach outings and even the obligatory Disneyland photos of two smiling kids wearing mouse ears.
It was difficult to believe those photos were of the same person who posed for selfies with orange-dyed hair, spooky black contact lenses and high-powered weapons and body armor, then stormed a crowded movie theater and opened fire.
Robert Holmes encountered that person in jail shortly after his arrest. He barely recognized the promising boy he'd raised.
"He was clearly very messed up," he said. "His eyes were bulging out of his head, and his pupils were dilated. He did tell us that he loved us, and that was good. But I could see something was really wrong with him."
He might not have been sick enough to fit the criteria for legal insanity, but he was and is seriously mentally ill, psychiatrist Metzner told the jury. His illness could ultimately sway jurors to spare his life.
Even if Holmes could appreciate he was doing wrong, the psychiatrist added, he still was influenced by a powerful delusion -- that he could avoid suicide and increase his own self worth by taking the lives of others.
"I think Mr. Holmes' actions on July 20 were a direct result of his mental illness," Metzger said.
"It all boils down to whether you believe he had a delusion or not."
Robert Holmes, a retired statistician, is undergoing cross examination and his testimony resumes Wednesday. His wife, Arlene, is expected to follow him to the witness stand before the defense wraps up its case.
The jury could begin deliberations by Thursday. Jurors have the day off on Friday.
If they decide the mitigating factors outweigh the aggravating factors, the trial is over and Holmes will spend the rest of his life in prison. If not, the trial resumes into another sentencing phase in which the jury will hear from shooting survivors and relatives of the dead -- people Holmes referred to as "collateral damage" -- who will testify about how the crime has changed their lives.