Acting on a tip-off, CBI officials caught the girls from four separate centres when they were using sophisticated gadgets, including bluetooth, to cheat during the examinations for MD courses conducted by PGIMER, CBI's DIG Mahesh Aggarwal said.
"We acted on a tip off and caught the girls, hailing from different parts of India, from four centres here. We also checked all the remaining seven centres where the examination was under progress.
"The modus operandi adopted by the accused was that they were sending out question papers using these gadgets and answers were being passed back to them through the same route," Aggarwal said.
In one case, a miniature device, which a girl had kept plugged inside her ear, got embedded inside, sources said, adding that she had to undergo a surgical procedure at PGIMER to take it out.
"We have booked the accused for cheating," Aggarwal said.
About 7,000 aspirants from various parts of the country were taking the examination, which is conducted twice a year, PGIMER's spokesperson Manju Wadwalkar said.