The CBI arrested former National Stock Exchange CEO Chitra Ramkrishna in the co-location scam case on Sunday, officials said. Ramkrishna was arrested in Delhi and was taken for medical checkup, they said. She was later lodged in lockup at the CBI headquarters, they said. The CBI had grilled Ramkrishna for three consecutive days and carried out searches at her residence, officials said, adding that she was not giving proper responses.

The central probe agency had also used services of a senior psychologist of the Central Forensic Science Laboratory who also questioned her, they said. The officials said the psychologist had also come to the conclusion that she was evasive in responses leaving no option for the agency but to arrest her. A special CBI court had on Saturday rejected her anticipatory bail application, they said.