The constable, Suryavadhini (32) of Pulianthope, is said to be working in the control room of Intelligence Section at the old commissionerate. When she stepped out of the premises late on Monday night, three men tried to snatch her chain. When she resisted, they started attacking her with a knife.

But the constable raised an alarm, after which the trio fled the scene. Suryavadhini was rushed to a nearby hospital for treatment. The Egmore police have registered a case and launched a hunt for the suspects.

Meanwhile, a bike-borne duo attacked and robbed a 30-year-old man of his mobile phone and cash in the wee hours of Monday near Annanur railway station. R Raguvaran (30), a call driver, was returning home on his bicycle when two men on a bike pushed him off his cycle and escaped with his mobile phone and Rs 3,000. The Tirumullaivoyal police are investigating. The Kodungaiyur police arrested three persons, including a juvenile, for robbing phone from a pedestrian at knifepoint. The aduo was remanded in judicial custody.