CASTLE ROCK, Colo. -- Two years after Brendan Bialy disarmed a gunman at the STEM School in Highlands Ranch, he relived that tragedy in a Douglas County District Courtroom.
Bialy was the first of six witnesses called to testify Friday against Devon Erickson.
Bialy said he and fellow classmates were getting ready to watch a movie in Mrs. Harper's British Literature class.
He said he couldn't recall whether the defendant was in the classroom when the movie started, but did notice him entering and exiting about 15 minutes later.
He also noticed that Erickson had a guitar case.
He said what was unusual was what happened moments later.
"The defendant drops the guitar case, draws a glock handgun and says 'nobody (expletive) move,'" Bialy recounted.
"Kendrick Castillo charges (at) him," Bialy said, "and ends up on the defendant's right side and pushes him up against the wall."
He said Kendrick was delivering blows to the defendant's right side.
"(The defendant) ended up firing one to two rounds," Bialy said. "I believe one of them hit Kendrick."
"Within two seconds Josh Jones comes up. Josh and I grab grab a side of the defendant and put him face down on the ground," Bialy testified.
"Did he willingly let go of the gun," Chief Deputy District Attorney George Brauchler asked.
"No," Bialy replied.
"Did he throw the gun down," Brauchler asked.
"No," Bialy responded.
During cross examination, defense attorney David Kaplan asked if there was anything about Erickson's behavior of particular note.
Bialy replied, "nothing I noted."
Kaplan asked if Erickson was pointing the gun up, as if ready to shoot above their heads.
Bialy said, "yes."
Kaplan asked, "pointed over people's heads?"
Bialy replied, "generally yes."
Under redirect, Bialy was asked how many times he punched Erickson, and when the defendant said he was sorry and that Alec McKinney made him do it.
Bialy said he punched the defendant about ten times.
"During the time he's being punched one through five, does he stop resisting," Brauchler asked.
"No," Bialy replied.
"Does he say, 'I'm sorry, Alec made me do it?"
"No,' Bialy said.
"After punches six through ten, does he say he's sorry," Brauchler asked.
Bialy said, "No."
"Tell the jury what's the first moment in your contact with the defendant when he stopped resisting and starts saying Alec made me do it," Brauchler said.
"When Josh is on top of him and I have gained possession of the handgun," Bialy replied.
"After you peeled the gun out of his hand? Brauchler asked.
"Yes," Bialy said.
Jurors also heard from FBI Agent Donald Peterson, who talked about FARO scan technology.
Defense attorney David Kaplan asked Peterson if there was an advantage to the 3-D scan compared to regular photos.
Peterson said, "you can determine distance and angles very precisely than you can with regular photos."
STEM School IT director Mike Pritchard testified that he saw Alec McKinney fighting with another student in the hallway, and that McKinney had a gun in his hand.
Pritchard said he took the gun, asked if it was McKinney's and McKinney said, "no."
Pritchard then continued into room 207 and saw Kendrick lying on the floor "unresponsive, but breathing."
He obtained the other gun that Bialy had wrested from Erickson, and placed them both against the wall.
School Nurse Karen Lewis and former health assistant Carol Knappich also took the stand, talking about Erickson's complaint that he wasn't feeling well, and appeared to be having an anxiety attack.
This was a few minutes before he said he was feeling better, left the health office and returned to the classroom.
The final witness, was Mitchell Kraus, a fellow student who escorted Erickson to the health office.
He said Mrs. Harper asked him to take Erickson to see the nurse because she didn't want him to go by himself.
After the hearing, John and Marie Castillo told Denver7 the bravery their son displayed was unbelievable.
"It's amazing how he saved so many lives," John said. "It's also painful. We heard testimony. Hearing it from his friends who were there that day, heroes like Brendan Bialy, just brings it all back."
"Seeing the video of our son's blood on the carpet, the descriptions of him laboring and breathing after he was shot, is something no parent should have to hear, see or relive, but we came here to see justice. We have to make ourselves strong and pray to a higher power and try to get through this, and that's what today and every day is going to be like," Castillo said.
He added that as tough as it was for him to see the blood on the carpet today, it was even more so for his wife.
He said he went to the STEM School after the shooting, because he wanted to see where his son died.
He said Marie didn't want to see that, so she didn't go.
"This was the first time she saw it," he said, referencing the photos and videos shown in court.
He said their hearts were heavy on a day they should have been celebrating their wedding anniversary.
The trial resumes Tuesday after the long Memorial Day weekend.