Liza was last seen in Emerson, New Jersey on August 19, 2007. Her husband, Joseph, stated they had an argument that afternoon. He accused her of having an affair and demanded a divorce. Liza walked away from the house afterwards, eastbound towards a nearby wooded area, and has never been heard from again. She left behind her cellular phone, medication, wallet, money, credit cards, cigarettes and all her clothes. She was reported missing to the police the next day by an anonymous phone caller.

The Murphys' marriage was troubled; Liza's family claims Joseph was verbally abusive and possessive of her, and the police were called to their home several times in response to domestic disputes. Joseph, an immigrant from Ireland, has no criminal record and no known history of violent behavior. Less than a week after Liza's disappearance, he jumped into traffic in an attempt to take his own life. He was struck by a vehicle and injured, seriously but not fatally. After this incident, he stopped cooperating with police in Liza's case. Joseph said the reason he tried to kill himself is because he was distressed about his wife's disappearance and the criminal investigation. He has since fully recovered from his injuries.

This was not the first time Joseph had attempted to commit suicide; a recovering alcoholic, he has been treated for depression and tried to kill himself in 1990 while he was separated from Liza. Liza herself has a history of prescription drug abuse and was involuntarily committed to a mental hospital for a brief period in 2005 after she threatened suicide. She spent eighteen months in counseling for depression and substance abuse issues. She also had ongoing disputes with her brother and a neighbor which resulted in disorderly person reports. It's uncharacteristic of Liza to leave without warning, however, despite her personal problems. She left behind three children, who are now in Joseph's care.

Extensive searches of the local area have turned up no signs of Liza. Authorities believe she may have been accosted after she left her home following the argument with Joseph. Her case remains unsolved.