A defense neuropsychologist diagnosed Marco Topete with attention deficit hyperactivity disorder but said his results were “dead in the center” of average on other tests.

Burlingame-based neuropsychologist Nell Riley testified Tuesday in the case against the accused cop killer.

Topete, 39, is charged with murdering Yolo County Sheriff’s Deputy Tony Diaz on June 15, 2008. He could face the death penalty or life in prison if convicted. He has pleaded not guilty to all counts.

Riley interviewed Topete for the first time in June 2009. She also interviewed him in December of that year.

“My diagnosis was that mr. Topete’s IQ was normal, memory and motor function was normal … but he did have a problem on a test set to test attention deficit disorder,” Riley said.

Riley had Topete take a computer-assisted ADHD test, which she said “was the only test where he had difficulty.”

Riley said symptoms of ADHD include not being able to pay attention but also being impulsive and not looking at the consequences of behavior.

The neuropsychologist also interviewed Topete’s family and looked at school records to see the suspect’s history with ADHD, which tends to start when people are young.

Under cross-examination from the prosecution, Riley said she also came to the conclusion Topete suffered “conduct disorder,” which is the adolescent equivalent of antisocial personality disorder.

“(Antisocial personality disorder) is a very controversial diagnosis,” Riley said.

She said the definition of antisocial personality disorder includes impulsiveness or failure to plan ahead, reckless disregard of the safety of others and lack of remorse. But Riley did not diagnose Topete with antisocial personality disorder.

Defense counsel Hayes Gable III said the defense hired Riley to conduct neuropsychology tests, not personality tests.

Further testimony from mental health experts will continue today, Wednesday and Thursday.

Gable said defense counsel would rest its case Thursday, anticipating rebuttals from the prosecution. Gable had initially said the defense’s case would take a month.

During opening statements Monday, Gable said Topete had suffered regular “night terrors” after he was released from prison on parole in March 2007.

On Tuesday, Dom Garcia, 18, testified his stepfather Topete would “wake up screaming” from nightmares.

Garcia’s mother, Angelique Topete, said during testimony Monday her husband would get little sleep as a result of the nightmares.

But Garcia also talked about the relationship he had with Marco Topete. He said they hung out “all the time” but Topete would watch his back more.

When asked about the day of the murder, Garcia began to cry and put a hand over his face. Judge Paul Richardson excused the jury for a few minutes so Garcia could gather himself.

Topete had asked Garcia to spend time with him that day, which happened to be Father’s Day. But Garcia decided to spend the day with his biological father in Merced.

“Marco was disappointed,” Garcia said.

On Father’s Day 2008, Topete went to a horse race with his cousin, Eduardo “Lalo” Velasco, who testified Tuesday to how much they were drinking that day.