A reward of Rs 50,000 was announced on the information leading to Patwari Harshvardhan, the main accused in the case, he said.
The Rajasthan Staff Selection Board had conducted the JEN exam on December 6, 2020 at various examination centres.
The board cancelled the exam after it was found that the question paper was leaked ahead of the exam.
The officer said on the basis of intelligence inputs, a team of SOG arrested Harshwardhan and a policeman from Nepal border.
The policeman was identified as Sub Inspector Rajendra Kumar Yadav alias Raju, aged 30.
The other two arrested were Rajendra Kumar Yadav, 55, a teacher, and Shivratan Mot, 30, a librarian. Both were arrested from different places.
All four had leaked the paper from a Jaipur government school and sold it to the candidates, the officer said.
The officer said that the accused told police during interrogation that the paper had been leaked from Shaheed Digvijay Singh Sumail Government Higher Secondary School, Khatipura, Jaipur.
Rajendra Kumar Yadav, employed as a teacher at the school, leaked the paper from the strong room, he said.
Rajendra Kumar Yadav alias Raju and librarian Shivratan Mot were assigned the task of distributing the papers to the candidates.
The hunt for other accused wanted in the case is still on, the ADGP said.