AUGUSTA — One of three teenagers accused of killing a Litchfield woman told police and psychologists he stepped in to help his friend kill his mother and briefly “choked out” the woman before he stopped because he just couldn’t go through with it.

So William Smith, 16, of Ashland, Massachusetts, turned away as his friend, Lukas Mironovas, 16, allegedly took over, strangling and then stabbing his mother Kimberly Mironovas to death as Smith could hear the sound of the knife going into her body, according to Carlann Welch, a Portland psychologist testifying as a witness for the defense of Smith.

Smith is in court this week for a bind-over hearing, to see if he will be tried as an adult or a juvenile on Class A felony murder and conspiracy to commit murder charges.

The other friend of Lukas Mironovas charged in the crime, Thomas Severance, 14, also of Ashland, Massachusetts, pleaded guilty in April to conspiring to kill Kimberly Mironovas. Lukas Mironovas’ still awaits a bind-over hearing to see how he’ll be tried, as an adult or a juvenile. The two were visiting the Mironovas household in April of 2018 when the incident occurred.

Welch, who spent the day on the stand Tuesday, said Smith told her he put his arms around Kimberly Mironovas and choked her out for a few or several seconds, but then he said he started crying and knew he couldn’t go through with killing the 47-year-old woman in April of 2018.

Welch said she was under the impression the teen meant, by “choke her out,” to make her pass out, not kill her.

But the teens had apparently planned to kill the elder Mironovas for much of the day of her death, first considering grinding up pills into a drink and serving it to her but deciding against that option after determining the pills wouldn’t dissolve in her drink. So they hatched a plan to strangle her instead, according to testimony Tuesday at the Capital Judicial Center.

When Lukas Mironovas was struggling with his mother, he called four or five times for Smith to come help, which Smith finally did, choking her briefly but then stopping, turning away and later leaving the room and running down the stairs.

Welch said Smith said in one of several interviews she had with him: “I couldn’t do it. I had to let (Lukas) finish. I started crying right after I put my arms around her neck.”

“He said he flipped out,” Welch said. “He stepped away when Lukas started choking her and stabbed her.”

Welch said Smith was scared, and already remorseful.

Prosecutor Meg Elam, a state assistant attorney general, said no one other than Smith himself has said he stopped choking Mironovas because he couldn’t go through with it. She called it a self-serving description of what happened that night.

She said Smith was the first of the three teens, who had attended school together in Massachusetts, to suggest they kill the elder Mironovas.

Welch said she thought Smith wasn’t being serious when he said that, and he didn’t think they would actually do it.

Elam argued that if Smith was scared or anxious, it was because he was afraid he would get caught because his fingerprints may have been on the knife and her body, and her blood had gotten onto his phone. She said being scared was not necessarily a sign of remorse.

“Did it occur to you he was flipping out because his fingerprints were on the knife and on Ms. Mironovas’ body?” Elam said to Welch during cross examination.

If Smith is tried as an adult, each charge against him could be punishable by up to 30 years in prison. As a juvenile, the most he could be sentenced to would be committal to a youth center until he is 21 years old.

In Severance’s case, for example, Judge Valerie Stanfill ordered Severance committed to the Long Creek Youth Development Center in South Portland. He will serve until he is is 21, the maximum sentence for a juvenile, according to the Attorney General’s Office.

Welch said testing and measurements of Smith indicate he is of very low risk of committing other acts of violence and would have a high probability of success if his issues as a youth, which include attention deficit disorder and substance abuse, were to be addressed at Long Creek. She said she thinks the public’s safety would be protected if he were to be committed to Long Creek and treated there until he is 21.

She said a measurement system, which compares juveniles to others in the justice system, indicated his “risk of dangerousness” is 97% less than the population of juveniles in the justice system, and he scored in the 99th percentile for his amenability to treatment.

She said he has a fairly strong family support system and is remorseful, as indicated in part by his difficulty talking about the killing.

She said he’s had relatively few reportable incidents requiring discipline at Long Creek. And she said his behavioral and mental health history were primarily “pro social,” versus anti-social, prior to her evaluation of him, other than his anxiety and regular use of marijuana.

Which prompted Elam to ask, “You left a big one out didn’t you? There’s one big non-pro social thing he did, he killed somebody.”

McKee said Lukas Mironovas, according to a transcript of his interview by detectives, said “I pretty much did everything.”

Welch said adolescents’ brains aren’t developed the same way as adults, nor are they the same as a child’s. She said their peers are very important to them, and they take more risks when they are with their peers.

“My opinion is (Smith’s) participation and assistance to Lukas was out of loyalty to Lukas,” she said. “His sort of moral code was put aside for loyalty.”

Smith, wearing a white collared shirt, sat quietly throughout Tuesday’s testimony, sometimes rocking back and forth in his chair. When he left the courtroom at the end of the day, he turned briefly to wave to his dad, Chris Sandoval, who watched the proceedings with Smith’s grandparents.

The hearing is scheduled to continue Wednesday.