The accused M Muniandi of Red Hills was under the influence of alcohol and picked up a quarrel with a sanitary inspector R Mathiazhagan since the latter was fining those not wearing masks near the Red Hills bus stand. Police constable Parthiban of Red Hills police station, who spotted the quarrel tried to intervene when Muniandi took out a knife and stabbed the constable on his thigh. Upon hearing his cries, passersby secured the attacker and handed him over to police who reached the spot on information. Parthiban was admitted to Padianallur health centre and given 10 sutures. Further investigation is on.