Thomas Severance, one of the three teenagers charged in the murder of a Litchfield woman last year, stands in court Tuesday with his attorney.

WATERVILLE, Maine — One of the three teenagers charged in connection with the death of a Litchfield woman last year has admitted to conspiring to kill her.

During a court appearance Tuesday in Waterville, Thomas Severance, 14, of Ashland, Massachusetts, acknowledged his role in a conspiracy to kill Kimberly Mironovas, 47, last April at her Litchfield home.

Two other teenagers, William Smith, 16, of Ashland, Massachusetts, and Lukas Mironovas, also 16, of Litchfield, are charged with murder in connection with the death. Lukas Mironovas was the victim’s son.

At Tuesday’s hearing, Severance entered a plea of no contest.

Justice Valerie Stanfill ordered Severance to be held at the Long Creek Youth Development Center in South Portland until he turns 21 — the longest sentence that can be imposed on a juvenile.

In exchange for the plea, the prosecution has agreed to withdraw a motion to have Severance tried as an adult. If Severance had been tried as an adult, he could have faced 25 years to life in prison.

Severance’s attorney, Kevin Sullivan, and Assistant Attorney General Meg Elam had reached an agreement on the sentence prior to Tuesday’s hearing.

Elam said that the state has filed motions to prosecute Smith and Mironovas as adults. The pair will also be tried together. Elam said hearings on whether they will be tried as adults have not yet been scheduled.

Kimberly Mironovas was found dead inside her home on Hallowell Road in Litchfield early the morning of April 22, 2018. An autopsy determined that she had been strangled and stabbed to death.

Little information has been released since the arrests last year, but on Tuesday, Elam shed light on what the state alleges drove the three boys to conspire to murder Kimberly Mironovas.

At the time, Smith and Severance were in Maine visiting Lukas Mironovas, who, with his mother, had recently moved to Maine from Ashland, Massachusetts.

Elam said the three teenage boys hatched the plot to kill Kimberly Mironovas after she allegedly discovered that they had stolen mairjuana from her bedroom while she was at school.

While on a walk with Mironovas’ dog, Elam said, “they began to discuss how they would kill [Kimberly Mironovas].”

The original plan was allegedly to crush prescription pills and put them in her wine, Elam said. The three also allegedly planned to slit her wrists to make it look like suicide. In making the plan, Severance used his cellphone to look up the lethality of prescription pills, she said.

According to Elam, Severance told police he did not want to be involved in slitting Kimberly Mironovas’ wrists because he didn’t want to “get into too much trouble.” As they were crushing the pills, Severance allegedly said he didn’t “think [the murder] is a good idea,” but he was reassured by Lukas Mironovas.

When they were unable to get the pills to dissolve in liquid, they allegedly came up with another plan.

The morning of April 22, Smith and Lukas Mironovas allegedly went into the victim’s bedroom while she was sleeping and stabbed and strangled her. After she was dead, they returned the knife to the bedroom to make it look like suicide, Elam said.

Severance said he stayed with the dog while Smith and Lukas Mironovas were allegedly killing the woman.

Elam said the three boys then took the marijuana, packed their bags and drove off in Kimberly Mironovas’ car, heading for Massachusetts. They instead were stopped by a Maine State Police trooper.

They told police that an intruder came into the house and they were going to get help, a story that Elam said they continued to tell investigators after Kimberly Mironovas’ body was found.

If they are tried as adults and convicted, Lukas Mironovas and Smith would face 25 years to life in prison on the murder charge. They would face up to 30 years in prison if convicted of the conspiracy charge as adult.