STEPHENVILLE, Texas: The man charged with killing former U.S. Navy Seal Chris Kyle, the subject of the blockbuster movie "American Sniper," acted coldly and deliberately in carrying out his deadly ambush at a Texas gun range, a prosecutor said on Tuesday.

In closing arguments, prosecutor Jane Starnes told a jury in the rural Texas city of Stephenville that Eddie Ray Routh, 27, bided his time before fatally shooting Kyle and Kyle's friend Chad Littlefield at the range about 70 miles (110 km) southwest of Fort Worth in February 2013.

"The defendant did the murder. How much clearer can it be? This is not a whodunit case," she said. Prosecutors presented video and audio evidence where Routh admitted to the crime.

Defense lawyers argued that Routh, a former U.S. Marine, was a paranoid schizophrenic and should be declared innocent by reason of insanity. They have not refuted charges Routh shot the two and fled in Kyle's pickup truck.

"That is not insanity. That is just cold, calculated capital murder," Starnes said. Prosecutors are seeking a life sentence without the possibility of parole.

Defense lawyer Tim Moore told the jury that Routh had been to VA hospitals four times because of his mental illness and was diagnosed as psychotic.

He asked jurors to look at a video of Routh taken into police custody several hours after the shooting where he admits to the crime in a rambling speech.

"You can see the delusional gibberish that he is talking," he said, adding expert testimony presented in court showed that he met the legal definition of insanity in Texas.

The judge told jurors they could find a person innocent by reason of insanity if the defendant did not know the conduct was wrong due to a severe mental defect.

SHOT AT CLOSE RANGE

A forensics expert called by prosecutors said Kyle and Littlefield were shot in the back at close range. They had no time to remove loaded guns that they had holstered.

"He (Kyle) absolutely never saw this coming," said crime scene analyst Howard Ryan.

Prosecutors said the two were shot by 12 or 13 bullets in total by Routh.

The trial has focused renewed attention on Kyle, credited with the most confirmed kills of any U.S. military sniper, and how he tried to help fellow veterans manage their mental scars by taking them for outings at gun ranges, sometimes with Littlefield.

"That compassion is what ultimately cost them their lives," prosecutor Starnes said.

Defense attorneys recalled a psychiatrist to the stand on Tuesday who said Routh had psychotic bouts of paranoia and suffered from schizophrenia at the time of the incident, believing he had to kill the two before they killed him first.

"It is my opinion that it is not a mood disorder that Mr. Routh suffered from," said Dr. Mitchell Dunn.

Prosecutors in a trial that has seen nine days of testimony had called a psychologist who testified Routh had a mood disorder made worse by heavy drug use and had been faking schizophrenia.

Routh served with the Marines in Iraq and Haiti. Prosecutors said Routh did not see combat in those deployments.

Reuters