A Dallas County jury sentenced today Mark Robertson to death for the 1989 slaying of 81-year-old Edna Brau at her Preston Hollow home.

John Brau, the victim’s son, said after the verdict that he hated to wish death on anyone but it was the only way to keep others safe.

“It’s been 18 years between the first trial and this trial. The only difference is he’s 18 years older,” Brau said outside the courtroom. “The jury saw the truth: He’s still a sociopath.”

Both prosecutors and defense attorneys called Robertson a sociopath Wednesday during closing arguments in front of jurors deciding whether he should face the death penalty or life in prison.

Dallas County prosecutors used the word to show why he deserved to die. But his defense attorneys, Robbie McClung and Richard Franklin, hoped to spare his life.

"This is not the anti-social-personality sociopath who killed three people in 1989," said McClung. "This is a changed man."

The jury deliberated about three hours before going home. They resumed deliberations this morning in the killing of Brau as she slept on her couch.

Robertson is already serving two life sentences for killing her grandson, Sean Hill, while they were fishing, and 7-Eleven clerk Jeffrey Saunders.

He had already been sentenced to die and was scheduled for execution five times. But a federal appellate court awarded him a new punishment hearing after ruling that instructions given to his original jury were confusing.

The instructions involved the jury's consideration of mitigating factors, including a defendant's abusive childhood.

Robertson was not abused. He witnessed his father beat and terrorize his siblings, according to testimony. His father then rewarded Robertson with money, candy and pats on the head.

McClung said these actions taught a young Robertson that people's lives had no value.

"His personality is being altered. His personality is being changed," McClung said about Robertson's childhood. "There is an effect."

As a teen, Robertson liked to stomp the heads of birds and strangle cats, according to testimony. He also once brought a gun to school. As an adult, he was charged with armed robbery.

Defense attorneys also said the jury should consider that he hasn't committed a violent act since 1989. A psychologist testified during the trial that Robertson's mental state has improved during the years he spent on death row.

But Dallas County prosecutors Pat Kirlin, Josh Healy and Ellyce Lindberg argued that Robertson's crimes and his potential to commit future violence mean he should get a death sentence.

Healy, in his comments to jurors, repeatedly called Roberston a "cold-blooded, sociopathic killer."

Prosecutors said that Robertson hadn't committed any other acts of violence because he was out of his element in prison. He preyed on the weak and defenseless, they said.

"You are a danger; you will always be a danger," Kirlin said, standing in front of Robertson. "And there is nothing in your background that is sufficiently mitigating."