Distrust of police and authority,as well as old grievances and social marginalisation may have contributed to disturbing scenes on Monday night.
NSW Police have asked for tougher knife-crime penalties despite data showing the overall rate of violent crimes involving blades has steadily fallen over the last decade.
Almost 11 years ago,Marina Solar was leaving a chemist in Leichhardt when her son,who has schizophrenia,stabbed her in the back of the neck with a serrated kitchen knife.