Jurors heard opening statements Friday in the trial of Brok Junkermeier, the 19-year-old charged with murdering his friend’s grandmother, Lila Warwick.

Junkermeier has pleaded not guilty to first-degree murder charges for allegedly carrying out the July ambush robbery and attack prosecutors say he planned with Warwick’s grandson, Robert Warwick, now 18.

Matthew Frank, assistant attorney general, told jurors that they’d soon see a four-hour video of Junkermeier being interviewed by investigators — describing the crime and telling investigators, “I killed Lila Warwick.”

Frank detailed how Junkermeier, wearing a black hoodie and ski mask, allegedly choked Warwick, 79, for 15 to 20 minutes but realized she was still breathing. Frank said Junkermeier tried to break her neck, “but she was still breathing.” So he then allegedly grabbed his knife and stabbed her several times “until blood came out of her mouth,” Frank said.

“He then took his mask off, because he was hot as hell,” he said.

Junkermeier’s attorney Kent Marshall gave a 3-minute opening statement. He said that Junkermeier killed Lila Warwick — “of that there will be no doubt.”

But he argued that doesn’t mean that Junkermeier is guilty of both the two charges, first-degree murder with premeditation and first-degree murder in the course of a burglary. The two charges are “very different in a lot of respects,” Marshall said outside the Kandiyohi County Courthouse. He declined to elaborate.

Robert Warwick’s trial has not yet been scheduled.

Jenna Ross • 612-673-7168