Sarah Barry, whose son Jack was stabbed to death, says she never knew he also carried a knife.
A woman whose teenage son was killed in a knife fight has said he could equally have been the killer.
Jack Barry, 19, was found injured on West Road, Hamstead, Birmingham, on 7 March last year and died at the scene.
His killer, 18-year-old Cameron Cheshire, was found guilty of murder and possessing a bladed article and jailed for at least 18 years in December.
Jack's mother Sarah Barry said she was "deeply ashamed" to learn that her son had also carried a knife.
She has agreed to be the face of the new Life or Knife campaign aimed at combating knife violence.
At the same time, West Midlands Police has introduced targeted patrols at times and in places where data shows most offences take place.
The force said since the Guardian Patrols began on 3 October it had seen a 29% reduction in serious youth violence compared with the same time last year across the force.