Ayouth attacked and stabbed a police constable, who had questioned him about a kitchen knife that he was carrying with him on Wednesday.
The constable Tarun Kumar Dutta, who was posted before the office of the deputy commissioner, central, of city police, challenged Mohammed Alim alias Mohammed Raja who had bought the knife from the New Market.
There was an altercation following which Raja stabbed Dutta in the abdomen and tried to escape, a police officer said.
However, locals caught hold of Raja and handed him over to police who arrested him.
Dutta has been admitted to the CMRI hospital. "He is now stable," the officer said.