READING (AP) — A mother has been ordered to stand trial on murder charges in the deaths two young children found hanging in an eastern Pennsylvania basement last fall.

A Berks County district judge district judge made the ruling Wednesday after hearing almost four hours of testimony in the case of 37-year-old Lisa Snyder. She’s charged with first- and third-degree murder, child endangerment, and evidence-tampering in the September deaths of 4-year-old Brinley and 8-year-old Conner.

Defense attorney Dennis Charles argued Wednesday that prosecution case amounted to only “speculation and guesswork.” Assistant District Attorney Margaret McCallum said Snyder was the only adult in the house when the children were found hanging in the basement of the Albany Township house. They died three days later.

Snyder has maintained that the children killed themselves. She had alleged that the boy was bullied, but authorities said there was no evidence of that, and he showed no sign of distress on bus security video that day. An occupational therapist said the boy wasn’t physically capable of harming himself or his sister in that way.

The judge scheduled Snyder’s formal arraignment for March 12. Prosecutors must let the court know by that date whether they plan to seek the death penalty in the event the defendant is convicted of first-degree murder.

Berks County authorities said the hearing was moved to Reading from a Hamburg district court office due to security concerns.