At 12:50 p.m. on May 7, Maria Castillo texted her son, Kendrick, at school, asking when he would be home.

When she didn’t receive a reply, she called. And called. And called.

But her 18-year-old boy — a teenager who loved robotics, fishing and the outdoors — never came home.

“My life is over. I don’t have a life,” Castillo told a Douglas County judge on Wednesday morning through an endless stream of tears. “He was my life.”

Castillo described the unbearable anguish of losing her only child during the final day of a legal hearing that will determine whether a 16-year-old accused in the killing will continue to be tried as an adult or whether his case will be sent back to juvenile court. Just a few feet away, Alec McKinney, the defendant, cried as Castillo talked.

For the past seven days, McKinney’s public defender and prosecutors from the 18th Judicial District Attorney’s Office have presented witnesses and made their arguments as to which court the 16-year-old’s trial should be held and if convicted, whether he should be housed in a juvenile or adult prison.

Douglas County District Court Judge Jeffrey K. Holmes will rule on Dec. 4 via written order.

Defense attorney Ara Ohanian promised that his client would plead guilty if the case was returned to juvenile court. District Attorney George Brauchler argued that a teen who planned a mass shooting for weeks deserves to be tried as an adult.

Kendrick Castillo’s mother was the last witness in the hearing, and it was the first time she has spoken publicly since her son was killed and eight others were wounded in the shooting at STEM School Highlands Ranch.

Maria Castillo said she drove to the school on May 7 after her husband, John, told her there had been a shooting. Kendrick wasn’t there so she drove to a hospital where she met with a doctor.

“The doctor said, ‘I’m sorry,'” Castillo said.

She didn’t know what that meant.

“He didn’t make it,” the doctor said. “He’s dead.”

Castillo punctuated her responses with tears and sniffles, recalling her boy as the “best son you could ask for.” Classmates have said Kendrick was the first student to leap from his desk and tackle a shooter in their classroom. Others who joined him in the fight also suffered gunshot wounds.

“I don’t want to eat. I don’t want to sleep. I don’t want to work,” she said. “I wish I could trade places with him.”

Maria and John Castillo go to Kendrick’s grave every day. They go in the cold. In the snow. In the rain.

“I tell him, ‘Goodnight,'” Maria Castillo said. “I tell him I love him.”

In closing arguments, Ohanian described the death and destruction at STEM as a tragedy. He never argued that his client was innocent but said McKinney deserved “a chance at a second chance.”

He described a child born into a home full of domestic violence, drugs and alcohol. McKinney suffered from an absentee mother and a system of mental health providers and the Department of Human Services that let him fall through the cracks, Ohanian said.

“Alec can redeem himself,” Ohanian said.

Brauchler summarized the prosecution’s arguments Wednesday, saying McKinney planned the shooting in advance, did not hesitate during the “heinous act” and showed no remorse afterward. The district attorney also noted McKinney has admitted to lying to medical professionals, his family and teachers about his drug use and homicidal thoughts.

“What message would be sent to the community, to other adolescents, if this case is sent to juvenile court?” Brauchler said.

After the hearing, John Castillo told reporters that it is important to the family for McKinney to be tried as an adult.

“Just because juveniles are looked upon as being young doesn’t mean that they don’t have the capacity to do mass homicide shootings and domestic terror,” he said, adding that lawmakers need to consider tightening the books on juvenile offenders. “We have to wake up to that, and that’s why this is so important. We need to set precedents.”

The Castillos did not miss a minute of testimony during the seven hearings, taking their customary seats every morning near the front of the court room. Day after day, they listened to attorneys outline the actions of a teenager sitting just feet away, someone charged with sparking the actions that killed their son.

“I look over and I keep looking for empathy, some type of human emotion,” John Castillo said of McKinney. “And I hate to say it, but I see crocodile tears.”