HOUSTON >> A man who claims he was insane when he fatally shot six members of his ex-wife’s family in their suburban Houston home, including four children, clearly understood he was doing wrong, and his actions were motivated by vengeance not mental illness, prosecutors told jurors at his capital murder trial today.

Ronald Lee Haskell had been scheming for months to carry out the “cold-blooded execution” of the Stay family in 2014, prosecutor Samantha Knecht said during closing arguments.

Haskell wanted to hurt anybody who had helped his ex-wife following their divorce and his anger drove him to create a meticulous plan to achieve that goal, authorities have said. He traveled from California to suburban Houston and stalked the family of his ex-wife, Melannie Lyon, for two days before launching his attack.

Knecht said Haskell’s actions before and after the shootings demonstrate he was not insane, including wearing a FedEx uniform to disguise himself so he could gain entry to the Stay family’s home. After the shooting, he reloaded his gun and headed to the homes of other Stay family members so he could complete his plan, she said. He was arrested before reaching any other homes.

“It’s up to you all to look at him and say, ‘No, you were not insane that day … We are going to hold you accountable,’” Knecht said.

Doug Durham, one of Haskell’s attorneys, admitted that his client committed a terrible crime, but said Haskell should be found not guilty by reason of insanity because he was suffering from serious mental illness that impaired his ability to know right from wrong.

Neal Davis, Haskell’s other attorney, told jurors medical records show that during the seven years before the killing, Haskell’s mental state was in a steady decline.

“He tried to get help for years. He didn’t want to be this way. He had no control,” Davis said.

A forensic psychiatrist testified at trial that Haskell suffered in part from schizoaffective disorder, a condition characterized by hallucinations or delusions.

Prosecutor Lauren Bard said today that Haskell’s actions showed he was “not a disorganized, psychotic individual. That is a man with a plan.”

Haskell’s claims of insanity and that he heard voices telling him to kill the Stay family were “just more lies and manipulation. It’s just more blame shifting. It’s what he’s done his whole life.”

Prosecution experts testified that Haskell had faked his symptoms.

“This was vengeance and it was not a serious mental illness,” Bard said.

Jurors began deliberating Haskell’s fate this afternoon following about three hours of closing arguments. The trial began Aug. 26.

An insanity defense is rarely used in Texas and seldom successful.

If the jury decides he’s not guilty by reason of insanity, Haskell would be sent to a state mental hospital and could stay there for a term equal to a life sentence. If convicted of capital murder, he could be sentenced to death.

Killed in the attack were 39-year-old Stephen Stay and his 34-year-old wife Katie, along with their children 4-year-old Zach; 7-year-old Rebecca; 9-year-old Emily; and 13-year-old Bryan. Katie Stay was the sister of Haskell’s ex-wife. Haskell is on trial for the deaths of Stephen and Katie Stay.

A fifth sibling, Cassidy Stay was also shot — in the head — but the teenager survived by playing dead.

Stay, who is now 20, testified at trial that she begged Haskell to “please don’t hurt us,” but he forced the whole family to lie face down on the living room floor before shooting them one by one.

Stay, along with other family members were in the courtroom during closing arguments. Haskell, 39, avoided eye contact and kept looking down at the floor.