Forensic psychologist Dr. Kirk Heilbrun evaluated Lindsay Clancy over three days and testified under oath:

- She has bipolar disorder.
- She has experienced no manic episodes.
- She was not manic when she killed her children.
- She never had psychosis, postpartum or otherwise.
- She had no hallucinations, auditory or otherwise (this means she lied about hearing a male voice commanding her to kill her children).
- She maintained full awareness during the murders and was in full control of her actions.
- She understood the illegality and, to a significant degree, the moral wrongness of her actions.
- She committed, in his words, "altruistic filicide" (murdering her children in the belief that they would suffer without her).

He concluded that she was "criminally responsible."