Lemak was born in 1957, was a surgical nurse, and lived in Naperville, Illinois. She and her husband David were divorcing, and he had begun a new relationship.
On March 4, 1999 she gave her three children sedatives and then suffocated them: Nicholas, seven, Emily, six, and Thomas, three. She then attempted to kill herself with an overdose and survived.
Her defence was insanity, supported by evidence of severe depression. The prosecution's case was that she had acted out of rage at her husband, and the jury rejected the insanity defence.
She was convicted of three counts of first degree murder in December 2001. The state sought the death penalty and the jury declined it; she was sentenced on May 30, 2002 to life imprisonment without parole.
This is a single act, not a serial case, and it is in the archive under that classification. As with several cases here, both sides accepted she was depressed and the dispute was whether it met the legal test, which the jury answered against her.