The police swung into action after employees of Kanpur Nagar Nigam and Kanpur Development Authority boycotted work in protest against the incident.

They, however, were back to work by the afternoon after the police picked up Vikramjeet Singh, a student of Sanathan Dharam Degree College, besides general secretaries of the students’ union — Anubhav Maurya, Dharmendra Yadav and Pramod. Two others are still at large. The arrested students denied the extortion charges but said they had scuffle with the official, Rajiv Shukla, on Saturday night.

Shukla said he was on his way to his Azad Nagar residence after visiting a relative when five persons stopped his car near VSSD College and demanded money for the student union’s oath-taking ceremony. When Shukla refused to pay, one of the youths allegedly took out a country-made pistol and “hit me under the right eye with the butt and took away Rs 1,000 kept in my wallet”. He said his wife Kiran, son Rishu and nephew Punnu were in the car at the time of the incident.

State Labour Minister Baadshah Singh had been invited as the chief guest at the union’s oath-taking ceremony, which now has been put off.