Before the collapses, Haskell had acknowledged with a quiet "Yes" a couple of questions put to him by State District Judge Mark Kent Ellis about his legal rights. Ellis ordered Haskell held without bond.
Tammy Thomas, the lead Harris County assistant district attorney in the case, said she had no idea what was going on.
"Maybe reality is finally setting in," she said. "It's not television, this is not fiction. He is facing his consequences."
Thomas said she expected a grand jury to issue a capital murder indictment as a result of Wednesday's shooting that killed Stephen and Katie Stay along with four of their children, ranging in age from 4 to 14.
Authorities have said Haskell was searching for his ex-wife, Katie Stay's sister, when he forced his way into the home in the northern Houston suburb of Spring.
He tied up the family and put them face-down on the floor before shooting each in the back of the head, according to investigators. The family had refused to say where Haskell could find his ex-wife.
The lone survivor of the attack, the couple's 15-year-old daughter, suffered a fractured skull when a bullet grazed her head but was able to call 911 and provide Haskell's identity and description.
Durham, who has been appointed by the court as the defense counsel, said his focus will be Haskell's mental condition "and whether he was legally responsible at the time of his conduct."
"Obviously the evidence is very compelling that he was responsible for the deaths of these children and his ex-wife's sister and her husband," Durham said. "It's a terrible tragedy. The question is: Is he legally responsible from a criminal standpoint?"
He said state and national laws say a person suffering from severe mental illness is not criminally responsible if they can't distinguish right from wrong.
"And I think the evidence is going to show ... he is a troubled individual and he has a history of mental illness. Unfortunately, the delivery of the health care has failed in this system."
Thomas said the defense strategy was not surprising, "because there aren't many explanations otherwise for him to grasp."
But she said the probable cause in the case showed a "determined effort involved, the planning, the conscious decisions."
She said she would present evidence to a grand jury to seek a capital murder indictment and a decision on the death penalty would be made later by elected District Attorney Devon Anderson.