Sobs filled a Douglas County courtroom the day before Thanksgiving as the mother of a teen killed in the STEM School Highlands Ranch shooting spoke about her son.

Throughout Maria Castillo's testimony Nov. 27, she worked to keep her tears at bay. Her agony became apparent, though, when she recounted the day she lost her only child.

“His eyes were closed and he was cold,” she said while weeping. “He didn't look the (same).”

Alec McKinney, the younger of two teens charged with carrying out the attack, also broke down in tears, his face contorting as he listened to the mother.

McKinney, 16, is charged with 43 counts, including first-degree murder, for the May 7 incident that left eight injured and Kendrick Castillo dead. The other suspect, Devon Erickson, 18, faces similar charges.

Maria Castillo was called by the prosecution in a hearing to decide if McKinney should be tried in juvenile or adult court. If moved back to juvenile court, McKinney's defense attorney promised he would plead guilty to all charges.

In the seventh day of the hearing, Judge Jeffrey Holmes listened as the prosecution called two final witnesses and both sides gave closing statements. A major argument between them was what minimum and maximum sentences exist in each court.

Holmes said he planned to release a written decision on which court McKinney will be tried in on Dec. 4.

A mother's testimony

Maria Castillo started by talking about what her son was like before the shooting.

“Kendrick was the best son I could have asked for,” she said.

She had already ordered the 18-year-old's graduation cards. They were planning a vacation. Soon, he'd be heading to college to pursue his goal of becoming an electrical engineer.

The morning of May 7, she hugged him, said "I love you" and sent him off to school, she said. About 1 p.m., she texted him to see if he'd be home after school.

Within a few hours, police were in front of Maria and Kendrick's father, John, asking what their son wore to school that day.

“They said `sorry,…he didn't make it. He's dead,'” she recalled.

Now, she and John take time every day to visit their son at Seven Stones cemetery.

“Even when we leave this court, it's dark and it's cold, we go there and tell him goodnight,” she said. “I tell him I miss him and that I love him so much.”

Defense attorneys, victim's families, McKinney, his friends and family and journalists in attendance all reached for tissues.

“My life is over,” she said. “He was my life.”

Maria Castillo added that she wished she could trade places with her son.

Possible sentences

Following a short break, the defense and prosecution gave final arguments for and against McKinney's return to juvenile court.

The teen defendant continued crying as his attorney, Ara Ohanian, spoke.

“I think Alec can redeem himself,” Ohanian said.

Ohanian reminded the court of previous days of testimony when they heard about the violence McKinney grew up around, his self-harming, depression and substance abuse.

McKinney also struggled with identity issues as a transgender boy, Ohanian said. He was born as Maya but adopted the name Alec after he began transitioning genders.

Ohanian argued that McKinney should go to a juvenile facility so that he can get needed mental health treatment, and the judge could see him again in about four years to decide next steps.

District Attorney George Brauchler responded by reiterating evidence that the attack was premeditated and targeted.

“It was not born of whim, but of hatred,” he said.

Brauchler and Ohanian disagreed about what mandatory sentences exist in the adult and juvenile courts. Ohanian said it was possible for the judge to give the teen life in prison through the juvenile court system if he wished.

Brauchler argued that the juvenile system could allow McKinney to get out early on good behavior or even get passes to leave the jail for the weekend. He also included concerns that the juvenile jail experiences many escapes.

He told the judge that sending McKinney back to juvenile court, where he could get a minimum sentence of a few years, would be a “dramatic injustice.”

“16-year-old or 100-year-old,” Brauchler said. “The acts (he) did lead us here today.”