The central probe agency took the step considering Bansal and his son Yogesh's seven-page suicide notes in which they had levelled allegations against some Central Bureau Investigation (CBI) officials for harassing and torturing them.
"We have today (Wednesday) received communication from Delhi Police enclosing therewith the purported hand written notes of B.K. Bansal... and his son Yogesh. It contains allegations against certain CBI officials in connection with the ongoing bribery investigation against Bansal and others," a CBI statement said.
Bansal was arrested on July 16 on charges of receiving a bribe of Rs 9 lakh for extending favours to a corporate firm. He was dealing with matters related to alleged violations by a Mumbai-based pharmaceutical company.
A Delhi court had granted bail to Bansal on August 30.
The statement further said: "We have examined the matter and decided to probe the allegations."
"CBI is fully committed to conduct investigation in a fair and professional manner without harassment to any one and strictly within the parameters of law. If any violation is established during the probe, strict action will be taken against the CBI officials concerned. The Competent Court will be informed," the statement added.
Bansal and his son were found hanging from ceiling fans by their maid when she entered the three bed-room flat on the first floor of Neelkanth Apartments in east Delhi's Patparganj area around 8.30 a.m. on Tuesday.
Bansal's body was found in the drawing room while his son's body was hanging in one of the bedrooms.
The twin suicides came two months after Bansal's wife and daughter ended their lives in a similar manner. Bansal's wife Satyabala, 57, and daughter Neha, 27, committed suicide by hanging themselves on July 19 after Bansal was questioned by the CBI.
