After arresting the topper of the JEE (Mains) examination in Assam and his doctor father for allegedly using an impersonator to write the test, the state police is looking for an owner of a coaching institute and an employee of a leading IT company in connection with the fraud in the country's prestigious engineering entrance exam.

Five persons have been arrested in the case so far and taken into police custody for five days, a senior officer said on Friday.

"The police are searching for an owner of a city-based coaching institute and an employee of a leading IT company," Additional Deputy Commissioner of Police (West), Guwahati Suprotive Lal Baruah told PTI.

Many people are suspected to be involved in the malpractice and the investigation is on to unearth the racket, another senior police officer said.

The state police approached the National Testing Agency, which has conducted the examination across the country, and sought information related to the JEE (Mains) exam to help them in their investigations.

The NTA had outsourced the infrastructural and human resources support to an IT company for conducting the examination, the police officer said.

Baruah is heading a special investigating team, set up to probe the scam, which came to light on Wednesday after an audio recording of the candidate's purported telephonic conversation with one of his friends went viral on social media.

The candidate admitted the fraud to a friend during a phone call which was recorded, police said.

The examination was held on September 5.

An FIR was filed by a person, identified as Mitradev Sharma, on October 23 in Azara police station here, alleging that the candidate, who scored 99.8 per cent in the JEE (Mains), had used an impersonator to appear for the test on his behalf.

Sharma alleged that on the day of the examination, the candidate entered the specified centre at Borjhar area, but came out after completing the biometric attendance with the help of an invigilator and another person wrote the exam.

The complainant also alleged that the parents of the candidate had paid Rs 15-20 lakh to the private coaching institute in Guwahati to help him in the examination.