The police say the students were so agitated that ``they were not concerned about safety of the passengers inside the vehicle.'' All the students are around 20 years old and study in different disciplines. The eight arrested have been identified as Umang Gupta, Bhagwati, Kumar Gaurav, Ashwini Kumar, Javed Akhtar Khan, Nitin Kumar, Harsh Tiwari and Janmajay.

On Monday, one of these students had boarded the bus plying between Nandnagri and Karampura on route number 234 from near his college. The student, whose identity the police have not yet ascertained, was on his way to Kamla Nagar.

The student claimed he was overcharged by conductor Santosh Kumar when he bought the ticket. A heated argument ensued and Santosh Kumar reportedly hurled abuses. The infuriated student got off at Kamla Nagar, but only after threatening to return. He also noted down the registration number of the bus.

The police say that yesterday, the student narrated the incident to some of his friends. The latter reportedly assured him that they would take revenge. A group of 10-15 of his classmate then positioned themselves near Patel Chest Institute near the college, and waited for the bus.

At around 6 p.m., they spotted the same bus. According to Santosh Kumar's statement to the police, the group blocked the road and forced the bus to stop. Then they dragged him out along with driver Sukhpal in full view of the passengers.

After beating them up, the group turned towards the bus. They reportedly started pelting stones and smashing the window panes. The shocked passengers barely managed to escape without injuries.

ACP (Civil Lines) Norbu Tshering said: ``I happened to be passing through the area a little later. When I spotted the bus and the pieces of glass on the road, I initially assumed that there had been an accident. But I got the real story after the conductor and driver recounted the incident.''

The police zeroed in on eight of the students later in the evening after Santosh Kumar reportedly said he had seen the youths running towards the Ramjas College compound. More students are expected to be arrested in connection with the incident.