Their mother, Lisa Snyder, has maintained that the September 23 hangings of her 8-year-old son and 4-year-old daughter were the result of a murder-suicide.
The children were in cardiac arrest when rescuers arrived and were revived, but later died at the hospital.
According to District Attorney John Adams, Snyder has maintained her son, Conner, wanted to take his own life because he was bullied and killed his sister Brinley so he wouldn't have to go alone.
However, investigators say there was no evidence Conner was bullied.
Investigators say there was a murder in that house - two, in fact - and the person responsible is the victims' own mother. She was arrested Monday and charged with first-degree murder and other offenses.
During a news conference, Adams detailed several inconsistencies with Snyder's story.
"Eight-year-olds, generally, that I am aware of, do not commit suicide, so of course we had questions," Adams said.
Snyder allegedly claimed that Conner took two chairs and a cable dog lead - that Snyder acknowledged picking up from a store the morning of the deaths - down to the basement.
She allegedly told investigators Conner said he was going into the basement to play. However, Adams said, a witness said the children rarely played in the basement.
Adams said the only known instance of them playing in the basement was after they received scooters for Christmas.
The children were hung from a cable dog lead that was wrapped around a rafter in the basement, and two chairs were found knocked over, Adams said.
Adams said an occupational therapist employed by Conner's school district said it would be "extremely difficult" for Conner to use the clasp on the dog lead or wrap the dog lead around the rafter to poor dexterity from a disability.
If Snyder was responsible, Adams was asked: How did Snyder get the children in position for her to allegedly carry out the hangings?
Adams said that was an unanswered question at this point, but was able to confirm the children did not have any drugs in their system. He could not comment as to whether the children had any other injuries.
Another unanswered question: what would have been her motive if she did do it?
Adams did not go into specifics about a possible motive. He did relate an alleged conversation between Snyder and a witness in which Snyder reportedly said she had "had enough."
Adams continued, "I don't know there is any explanation for her behavior at all. I don't think I can stand up here, nor anyone, and explain the horrific loss of two innocent children's lives."
Lisa Snyder was the person who called 911 after finding the children hanging in the basement. However, investigators questioned why she didn't do anything to help her son and daughter.
Adams said Snyder never returned to the basement after making the 911 call.
"I would agree that we all may think that a mother whose children were found hanging would make every effort possible to save them. That was not done in this situation," Adams said.
Adams also detailed several Google searches that were found during the investigation:
-Sept. 17, 2019: Carbon monoxide in a car how long to die
-Sept. 20, 2019: Almost got away with it best episodes
-Sept. 22, 2019: Hanging yourself
Also on September 22, Snyder also allegedly visited a website that details a method of hanging.
-Sept. 23, 2019 (the day the children were found hanged): Does a hybrid car produce carbon monoxide
Several devices were seized from her home, including a laptop, several iPads, and the phone used to call 911. However, Adams said investigators have been unable to locate a Samsung device that, they believe, was used to order the cable dog lead.
Adams also revealed that Snyder's children were removed from her care in 2014, but were returned in 2015. CYS had been involved with this family until November 2015 when the case was closed.
When asked if he could reveal why CYS intervened, Adams said "I cannot. Maybe at a later date, but at this point, I could not elaborate on that."
Because she is charged with first-degree murder, Snyder is not eligible for bail. Adams said there has been no determination yet as to whether prosecutors would seek the death penalty.
Snyder is being held without bail, and had no comment for reporters as she was escorted from a state police barracks.
Investigators say they also found images of the suspect abusing a dog during the investigation.