Accused STEM School Highlands Ranch shooter Devon Erickson – facing life in prison without parole if convicted of first-degree felony murder – told a judge Friday that he will not testify in his own defense.

That likely leaves jurors to decide his fate on 48 charges connected to the May 7, 2019, school shooting that left one student dead and eight others injured with just the testimony of two defense experts – a University of Colorado Boulder professor and a toxicologist.

Defense attorneys David Kaplan and Julia Stancil are expected to rest their case Friday morning. Attorneys for both sides are expected to make their closing arguments to the Douglas County District Court jury on Monday and the jurors will then begin deliberations.

Prosecutors have called more than three dozen witnesses – most of them students and teachers who either saw or fled the classroom when Erickson pulled a handgun from a guitar case and fired – and offered more than 200 exhibits in an effort to convict the 20-year-old on charges ranging from murder to criminal mischief and attempted theft.

Defense attorneys have not said Erickson wasn’t responsible for the death of Kendrick Castillo or that he wasn’t a part of the shooting with already-convicted co-defendant Alec McKinney. What they have said is that Erickson was an unwilling participant who hoped to stop the shooting but was too afraid to warn anyone because McKinney had threatened to harm him.

CU Professor Roger Enoka, a physiology expert, on Thursday testified that it was highly likely that Erickson unintentionally fired the handgun, killing Castillo, when three students startled him as they rushed him.

With frequently dramatic detail, McKinney testified that the plot was actually Erickson’s, recanting earlier statements that he was solely responsible and had forced Erickson to comply.

McKinney said the two planned to lay the blame on McKinney, who was a 16-year-old sophomore at the time, and Erickson would kill his accomplice to appear the hero after killing all the students in the classroom. Prosecutors pointed out that Erickson magnetically locked the door behind him before he pulled the handgun.

McKinney, now 18, also said he intentionally fired a revolver until it was emptied of the nine bullets it held, then continued to pull the trigger several more times.

The two planned the incident for several weeks, McKinney testified, agreeing to make it all appear McKinney’s idea – a resolve they continued through questioning by police. Videos they filmed of McKinney forcing Erickson to comply with orders to ingest cocaine and break into a gun cabinet in Erickson’s home were actually a ruse, McKinney testified, to make their plan appear real.

McKinney testified that Erickson earlier told him he had a bucket-list item to kill someone and get away with it.

While Erickson was tackled and disarmed by two students – Castillo was already on the ground with a fatal wound – another student and a teacher were disarming McKinney in the hallway, according to testimony. McKinney somehow got free and retrieved a second handgun from a backpack, then put the gun to his head but didn’t fire. A school security guard disarmed and handcuffed him for police.

McKinney is serving a life sentence plus 38 years after pleading guilty to first-degree felony murder and more than a dozen other charges. Because he was a juvenile at the time of the shooting, he is by law eligible for parole after 40 years.