The Southport Magistrate's Court heard accused murderer Kaihana Tahsseen Hussain told police her father had once threatened to kill her if she abandoned the Muslim faith.
Hussain has been charged with murdering her mother, Shaheda.
A forensic officer told Hussain's committal hearing yesterday that police also told her the defendant had alleged that her mother had tried to strangle her during an argument three months before the October 2006 tragedy.
Anne-Louise Swain said the teenager's injuries were consistent with her claims that her father Muhammad killed his wife and tried to kill her before turning the knife on himself.
However, Dr Swain could not say categorically whether the teenager's injuries were sustained fending off an attack or from performing the attack.