Sources indicated that the CBI inquiry has been recommended following instructions from Defence Minister Manohar Parrikar.
On Monday, the army had ordered a high-level court of inquiry (CoI) into the alleged leak of question papers for the army's recruitment examination for soldiers.
Eighteen people, including a retired serviceman and paramilitary personnel, have been arrested during raids in Maharashtra and Goa since last Saturday.
On Sunday, the army had cancelled examinations at a number of centres including in Kamptee, Nagpur, Ahmednagar, Ahmedabad, Goa and Kirkee which come under the Pune zone.
The sources said the tests at some other centres may be countermanded based on findings of the inquiry.
The examinations were held on Sunday for a number of posts including those of soldier clerk, strongman and soldier tradesman at 52 centres across the country.
Nearly 250 students have also been taken into custody in connection with the paper leak.
The students were allegedly given the exam papers by those who run various coaching classes and some army employees to write the answers in lodges and other places.