READING, Pa. (AP) — A judge on Friday rejected a plea agreement for a Pennsylvania woman charged with killing her two young children, who were found hanging in the basement of their home nearly four years ago.

Lisa Snyder, 40, sought to plead no contest but mentally ill to two counts of third-degree murder in the September 2019 deaths of 4-year-old Brinley and 8-year-old Conner. The children were taken off life support and died three days after they were found in the home in Albany Township, about 60 miles (97 kilometers) northwest of Philadelphia.

Berks County President Judge Theresa Johnson rejected the plea as soon as it was presented to her by a prosecutor and ended the hearing after just a few minutes, shutting down a defense lawyer who tried to interject.

“I am not accepting that plea agreement,” Johnson declared, adding, “It doesn’t serve the interests of justice.” She then stalked out of the courtroom.

The case will now head to trial, where Snyder faces charges of first-degree murder, child endangerment and evidence tampering.

District Attorney John Adams declined to say why prosecutors had agreed to let Snyder plead no contest to the reduced charge of third-degree murder, which carries a sentence of 20 to 40 years in prison.

“We don’t contest the fact that she’s mentally ill, and she meets the threshold set up under the law that she is mentally ill,” he said in a phone interview after the hearing.

Snyder’s defense lawyers had no comment as they left the courtroom.

Snyder, who made the initial 911 call, had told police her son was bullied and had been threatening to take his own life. But authorities were immediately suspicious of her claim of suicide, and said they found no evidence to support it. The boy showed no outward signs of trouble on school bus security video recorded that day, and an occupational therapist later said he wasn’t physically capable of causing that kind of harm to himself or his little sister.

Police said they found evidence that Snyder went online for information about suicide, death by hanging and how to kill someone, and that she’d also looked for episodes of a documentary crime series called “I Almost Got Away With It.” Snyder also admitted going to a store to buy a dog lead on the day the children were found hanging from it, authorities said.

A coroner said both children were killed by hanging and ruled the deaths homicides.

“I don’t think that I can stand up here, nor can anyone, explain the horrific loss of two innocent children’s lives. I think it goes without explanation,” Adams, the prosecutor, told reporters when Snyder was charged in December 2019, more than two months after the killings.

The defense had planned an insanity defense, citing a “chronic history of severe mental disorders.” Her lawyer has said Snyder had severe depression, borderline personality disorder, dissociative disorder and other mental illness at the time of the homicides.

Prosecutors had indicated they would seek the death penalty.