Police are investigating a perjury complaint against the mother of a police constable present when a fellow officer shot dead Waitara man Steven Wallace in 2000.
Wallace was shot when he threatened Constable Keith Abbott with golf club and a baseball bat on Waitara's main street in 2000.
Now Wallace's mother Raewyn Wallace has lodged a perjury complaint against Patricia Dombroski, mother of Constable Jason Dombroski, who was with Mr Abbott at the time of the shooting.
Mrs Wallace alleged Mrs Dombroski gave false evidence at the Wallace family's failed private prosecution of Mr Abbott for murder in 2002, The Taranaki Daily News reported.
Mrs Dombroski, a family court co-ordinator at New Plymouth, told the court that two weeks before the shooting she had received a phone call from a woman concerned that her son, whom she identified as Steven Wallace, was becoming increasingly violent and threatened to kill her,
Another woman with the surname Wallis later came forward to say she had made the call. Mrs Wallace said the wrong information had stopped them from getting a fair trial.
Detective Inspector Sue Schwalger, crime services manager for the central region, said she did not know how long the investigation would take.
"I've met with Raewyn Wallace and the information that she has supplied is being investigated."