Neighbors gather behind police barrier tape at the scene of a shooting during which eight people were killed, in Houston, Texas August 9, 2015. [Photo/Agencies]

HOUSTON - A family of six children and two parents were killed at a Houston home by a man with a violent criminal history who had previously been in a relationship with the mother, authorities said Sunday.

David Conley, 48, was charged with capital murder in the deaths. Conley, who is being held in Harris County Jail, didn't appear at a court hearing Sunday where an arrest affidavit was read. The judge denied him bond.

The dead were identified as parents Dewayne Jackson, 50, his wife Valerie Jackson, 40, and children Nathaniel, 13, Dewayne, 10, Honesty, 11, Caleb, 9, Trinity, and Jonah, 6. Nathaniel was believed to be Conley's son from the relationship with Valerie Jackson. Police had earlier said that there were three adults and five children killed.

"We do not - cannot - fully comprehend the motivation of an individual that would take the lives of so many innocent people. Especially the lives of the youngest," Harris County Chief Deputy Tim Cannon said. "The killer's motives appear to be related to a dispute with Valerie, who was a former domestic partner."

Conley told police that he discovered on Saturday morning that the locks had been changed at the home after he had moved out. He entered the home through an unlocked window, according to the affidavit.

Officials with the Harris County Sheriff's Office later responded to a request to do a welfare check at the house and got no response at the door. They saw through a window a male on the floor with a gunshot wound. Police then heard gunshots coming from the front of the house. A standoff ensued between officers and Conley. He later gave himself up to authorities and was arrested.

Court records show Conley's criminal history dates back to at least 1988, with the most recent incident last month, when he was charged with assault of a family member. In court documents, authorities say the suspect had been arrested for allegedly assaulting the woman he was living with at the home where the bodies were found. Documents say he was in a dating relationship with the woman. It was not immediately clear if the woman in the previous incidents was Valerie Jackson.