Police have accepted they made a number of mistakes investigating a teacher and student's relationship.
In 2014, police received an allegation of inappropriate contact between Gisborne teacher Sam Back and 13-year-old student Reiha McLelland.
The pair exchanged almost 4000 text messages, but police concluded there was insufficient evidence of offending.
An Independent Police Conduct Authority investigation found the investigation by police into former teacher Sam Back's relationship with student Reiha McLelland was "flawed".
Reiha eventually took her own life.
Independent Police Conduct Authority general manager Warren Young told Larry Williams the investigating officer made a number of errors.
"He didn't properly work through the text messages identifying the most concerning ones. The information which was obtained was clearly not set out in the file. In the end the investigation was flawed."
LISTEN ABOVE AS WARREN YOUNG SPEAKS TO LARRY WILLIAMS