– Brok Junkermeier brought his murder trial to a sudden and surprise end Wednesday, pleading guilty to the brutal murder of his friend’s 79-year-old grandmother.

Testifying in Kandiyohi County District Court early Wednesday afternoon, Junkermeier, 19, said he was changing his plea because he had killed Lila Warwick and wanted to keep “the families from having to listen to more of the evidence.”

“You don’t want anybody to have to hear any more,” his attorney Kent Marshall said.

“No, I don’t,” Junkermeier said.

They already had seen and heard plenty during the four days of testimony.

Prosecutors had played a four-hour, videotaped interview of Junkermeier admitting to strangling and repeatedly stabbing Warwick. They had shown photos of Warwick bleeding on her basement floor. When a deputy unboxed the 20-inch dagger Junkermeier had used, a granddaughter put both hands to her mouth.

Wearing a tie, glasses and a somber look Wednesday, Junkermeier pleaded guilty to first-degree, premeditated murder, admitting that he had sneaked into Warwick’s house with the dagger intending to “rob and kill her.” He said that he had plotted the July robbery and murder with Warwick’s grandson, Robert Inocencio Warwick, since December 2012.

The penalty for first-degree, premeditated murder is life in prison without parole. Sentencing will be held April 9, when Warwick’s family will make a statement.

Robert Warwick, 18, faces first-degree murder charges for allegedly planning his grandmother’s death. His trial has not yet been scheduled. Devon Jenkins, the 16-year-old who acted as the lookout, was sentenced as a juvenile in January for aiding and abetting second-degree murder.

On Wednesday morning, jurors had watched the conclusion of the videotaped interview, listening to Junkermeier describe how he had killed Lila Warwick, using his own body to show where he stabbed her “six, seven times” after choking her and breaking her neck.

“One, two, three, four,” Junkermeier said, hitting points on his chest and abdomen.

He told investigators where they could find evidence. The ski mask was stuffed under the seat of his car. The shoes were thrown into the garbage next to his house. They’d discover the dagger in the yard of an abandoned farmhouse.

Junkermeier and “Robbie” Warwick had expected to find tens of thousands of dollars in the safe they picked up on a trip back to her home a few hours after her slaying.

But when the pair pried open that safe, “there was just, like, documents,” Junkermeier said in the video, including a passport, high school diploma and baptism certificate. They also found $30,000 in savings bonds in the name of Lila Warwick, which deputies later spotted on Junkermeier’s bedside table — just where he had said they’d be.

Later in that interview, when asked with what crimes he ought to be charged, Junkermeier didn’t hesitate.

“First-degree murder,” he said. “I’d say premeditated murder. Accessory to murder also …”

Marshall didn’t learn of Junkermeier’s intention to plead guilty until after arriving at the Kandiyohi County Courthouse on Wednesday morning. “This came as a complete shock to everyone,” Marshall said.

Junkermeier had previously pleaded not guilty to the two charges he faced — first-degree, premeditated murder and first-degree murder in the course of a burglary. Marshall had planned to argue that the second charge, which offered the possibility of parole, was a better fit.

In a courtroom cleared of jurors Wednesday, Marshall and Judge Donald Spilseth questioned Junkermeier, asking whether he understood his right to a trial, his ability to present witnesses and the coming punishment. Junkermeier said that he understood, often answering, “Yes, sir.”

Marshall noted in his questioning that a psychologist who evaluated Junkermeier months ago “found a number of mental disorders,” including autism, Aspergers syndrome and anti-social behaviors.

Picked on and bullied in grade school, “this was the first time in Brok’s life where people were paying attention to him,” Marshall said later. “I think that he was, to some degree or other, playing the big shot.”

Before Junkermeier left the courtroom, Marshall grasped the tall young man’s arms.

“Brok, you’ve done a horrible thing but that doesn’t mean that you’re a horrible person,” Marshall recounted saying. “There are good parts to you, and I hope you find a way to use those good parts once you get to where you’re going.”