A South Carolina father accused of killing his five young children by exercising one to death and strangling the other four was found guilty and mentally viable on Tuesday, allowing prosecutors to seek the death penalty.

Timothy Jones Jr., 37, was found guilty of the August 2014 killings inside his home in Lexington County, located outside Columbia, S.C. The children were between one and eight years old. The jury did not find him mentally insane.

PROSECUTOR: FATHER WHO KILLED KIDS IS SELFISH, EVIL MAN

Throughout the trial, defense attorney Boyd Young argued that his diseased and damaged brain kept him from knowing both legal and moral right from wrong when he killed his children — the requirement under South Carolina law to find him not guilty by reason of insanity.

The same jury will return Thursday to begin hearing evidence from prosecutors who will portray him. as a selfish, evil father who decided-- after killing one child-- that all his children should die instead of ending up with his ex-wife.

His lawyers are expected to argue he was a doting, single father who put himself through college while married with children. They will portray him as a computer engineer with an $80,000-a-year job whose mental issues worsened until stress from his wife's alleged infidelity and drug use drove him over the edge.

The man confessed to killing his 6-year-old by forcing him to engage in excessive exercise after damaging electrical sockets around the house. He admitted to eventually strangling 8-year-old and 7-year-old with his hands and using a belt to choke 2-year-old Gabriel and 1-year-old Abigail because his hands were too big, prosecutor Rick Hubbard said in his closing argument Monday.

Jones Jr. wrapped all five bodies in garbage bags and drove around the southeast for nine days before eventually disposing of them on a hillside near Camden, Ala. He was arrested a short time after in Mississippi.

CLICK HERE TO GET THE FOX NEWS APP

HIs mother has been in a mental institution for more than two decades with schizophrenia, and the defense called several experts to suggest Jones had the mental illness too, but it was never diagnosed.

The Associated Press contributed to this report.