PATNA, June 3 -- Three people, including the director of a coaching institute, have been arrested after a violent clash outside the coaching centre of educator Faisal Khan, popularly known as "Khan Sir", in Patna's Kadamkuan area on Tuesday night, police said.

The attack left a security guard injured, prompted large student protests and sparked an ongoing probe into possible rivalry between coaching centres, police added.

The three arrested were identified as Roshan Anand, director of Gyan Bindu coaching institute; Prince Gaurav; and Abhishek. They were produced before a local court and remanded in judicial custody on Wednesday.

The exact nature of the attack remains under investigation.

"We were inside while teachers were taking clas...