The killings were unfathomable, the crimes unspeakable, and Daniel William Marsh was sane when he committed them, a Yolo Superior Court jury found Tuesday.

Marsh was 15 when he broke into Oliver Northup and Claudia Maupin’s south Davis home in the predawn hours April 14, 2013, and savagely murdered the elderly pair. The jury convicted Marsh, 17 now, last week of first-degree murder.

On Tuesday, jurors, some shaken so deeply by the evidence that they asked for counseling, concluded the Davis teenager was of right mind when he attacked the couple in their bedroom with a hunting knife.

With the sanity finding, the panel quickly rejected Marsh’s plea that he was not guilty by reason of insanity. A Nov. 12 hearing will determine when Marsh is sentenced.

Many jurors declined to talk about the case. One who declined to be identified said of reviewing evidence of the crimes, “It was very bad. None of us were able to go to sleep. The details – it was very difficult.”

Jury foreman Stephen Fleming of Davis briefly “thanked the criminal justice system. Davis Police Department and the FBI worked together to provide a great amount of evidence for us.”

Marsh has been held in Yolo County juvenile custody since his June 2013 arrest and will stay in youth custody until he is 18, when he is transferred to state prison, said his attorney, Yolo County Deputy Public Defender Ronald Johnson.

Johnson said he planned to file an appeal.

Marsh’s mental health during and before the brutal killings was a dominant feature of the weeks-long trial, adding a complex layer to the case, prosecutors said at a Yolo County district attorney’s news conference following the decision.

If Marsh were found insane, prosecutors said, he would have been hospitalized in a state facility until determined to be sane, then released.

Marsh’s ruinous childhood and family life; his insistent thoughts of homicide, suicide and violent dreams; therapy; hospital stays for anorexia and depression; and assortments of antidepressants stated a case for Marsh’s mental instability.

The case “was very complex because of the mental health issues,” said Michael Cabral, assistant chief deputy district attorney and lead prosecutor on the case, calling Marsh “one of the most troubling defendants I’ve ever prosecuted.”

“The public perception is that you think you’d have to be insane” to commit such acts, Cabral said.

Indeed, a shocked Davis wondered aloud how anyone, let alone a 15-year-old, could dream of, then unleash such horror. Northup was 87; Maupin, his wife, 76. Residents wondered who might be next, whether anyone was safe.

“A cloud of fear descended over the city of Davis,” Davis Police Chief Landy Black said of the days after the grisly deaths.

He had seen Northup and his band perform a day earlier. Black had never met him. It would be the first and last time he saw Northup alive.

“There was a sense of shock for everyone. It made everyone feel more vulnerable,” Black said after the news conference. “Chip and Claudia were involved in music, politics, they were as normal as anybody. People thought, ‘That could be me.’ There was so much about this that personalized it.”

At the Woodland news conference, Black and family members seemed to rely on myth and Scripture, using words like “bogeyman,” and “devil” to describe Marsh and the killings.

But under California law, Marsh had to prove he did not understand the nature of his act and could not distinguish right from wrong at the time of the killings for the jury to find him insane.

Sacramento attorney William J. Portanova said an insanity defense is unusual and rarely convinces a jury. Unless the defense can prove definitively that a defendant had no idea that what they were doing was wrong, juries won’t buy the defense, he said.

“Jurors are simply not willing to give the benefit of the doubt on these matters, whether it be a crazy kid from down the block or more advanced, more sophisticated killers doing it for hire,” Portanova said. “The insanity defense is really about excusing someone who didn’t know what they’re doing, and that’s an extra high burden to meet.”

Cabral and his co-counsel, deputy district attorney Amanda Zambor, said the evidence showed Marsh did know what he was doing.

Marsh stole a ski mask, sharpened a hunting knife, then set out with plans on what he was going to do with both.

“He wandered around the streets of Davis. ... He understands it’s legally wrong. He climbs in that window, he stood over that bed. When Claudia stood up, he pounced on her,” Cabral told reporters. “He expressed pride that he was now a murderer, then bragged about it to his friends.”

In the end, Victoria Hurd said the words her mother Claudia would have said: “Thank you.”

She thanked the helpers, the people her mother told her as a child to look for when she was frightened. She thanked the prosecutors who she said slayed the devil in their midst. She thanked the jurors who convicted the troubled teen who took away Claudia and Chip.

“There’s hope because there’s humanity,” Hurd said. “Thank you. That’s what Mom would say.”