Lawyers defending a father charged with killing his five children turned Wednesday to brain science and their client's odd statements to try to spare him from a possible death sentence.

The insanity defense case for Timothy Jones Jr. began after a week of emotional testimony in which the children's sobbing mother had to be aided from the courtroom and jurors heard disturbing discussions of strangulation marks and decomposing bodies. The children, ages 1, 2, 6, 7 and 8, were killed in their Lexington home.

In videotaped testimony replayed Wednesday, Dr. Travis Snyder showed MRI images and other photos of Jones' brain taken in April 2018, four years after the slayings. The images showed what appeared to be an indentation in Jones' skull that his lawyers have said was caused by a car crash Jones was in as a teenager. Snyder then showed other images of the brain that showed places where there had been bleeding and other damage.

"Given his injuries, it's possible the electrical functions of his brain were not working properly," Snyder said.

The doctor added that the damage he saw was similar to that seen in brains of people diagnosed with schizophrenia. Defense attorneys have said Jones had the disorder, but it had never been diagnosed, and that his mother has been in a mental institution for 20 years.

Snyder also testified that people with damaged brains can still graduate from college or regulate their emotions. The defense team said in opening statements that while Jones had an $85,000 job as a computer engineer, he had a thin grasp of reality. He experienced a psychotic break, they said, due to the infidelity of his ex-wife, the children's mother; the difficulty of raising five young children on his own; and a feeling he was failing to live up to his religious beliefs.

The defense also revisited Jones' confession to police, asking Lexington County Sheriff's Sgt. Anthony Creech to focus on the odd things Jones said, such as that one of his five children was going to grow up to do something bad and he prevented that by killing all of them. Jones also said he feared his children were trying to kill him or that he heard voices in his head. He said the voices got louder after the slayings.

"A voice says, 'Why don't you burn the bodies?' Another voice says, 'Why don't you cut them up and feed them to hogs?' Another said, 'Why don't you put them in concrete?'" Jones said, crying on the recorded confession. "I don't like those voices."

Prosecutors called more than 30 witnesses to the stand, including school administrators, the family's babysitter, police officers and the ex-wife, Amber Kyzer.

In his confession, Jones said he forced the middle child, 6-year-old Nahtahn, to exercise for hours as punishment after he broke an electrical outlet. He said when he found the child dead, at some point after Nahtahn had gone to bed, he flew into a range and strangled the other four kids.

Jones said the oldest child, 8-year-old Mera, said, "Daddy, I love you," as her father wrapped his hands around her neck, FBI agent David Mackey testified.

After all the children were dead, Jones wrapped their bodies in plastic and started searching on his smartphone for tips on how to dispose of bodies and get away with crimes, police officers testified.

He drove aimlessly for several days around the Southeast U.S. with the bodies in the back of his SUV before putting them in garbage bags and leaving them on a hillside in Camden, Alabama, prosecutors said.

When he was arrested in Smith County, Mississippi, officers found a checklist written in the car that included "melt bodies" and "saw down bones."

When investigators asked him about it during his confession, Jones started to cry.

"I tried to saw a leg and I couldn't bring myself to do it," he said.

The trial is being livestreamed from the Lexington County courthouse.

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