MUMBAI - The Central Bureau of Investigation (CBI) has filed a case of criminal conspiracy and fraud against the former chief executive of ICICI Bank Chanda Kochhar and her husband Deepak Kochhar, according to a statement from the agency on Thursday.

The CBI case is the latest twist in a controversy that has dogged ICICI and Kochhar for months, and that was instrumental in her decision to step down last October.

The CBI alleges that Kochhar favored Videocon Industries, a consumer electronics and energy exploration firm, in the bank's lending practices. Videocon's founders had an investment in a renewable energy company founded by Kochhar's husband.

The CBI also filed a case against Venugopal Dhoot, the managing director of the Videocon group and two of Videocon's subsidiaries.

"The accused sanctioned certain loans to private companies in a criminal conspiracy with other accused to cheat ICICI Bank," the CBI statement said.

Chanda Kochhar, Deepak Kochhar and Venugopal Dhoot were not immediately reachable for comment.

ICICI Bank did not respond to requests for comment from Reuters. Videocon officials were not reachable for comment.

Nupower Renewables Ltd and other "unknown public servants and other unknown private persons" have also been booked, a copy of the information report filed by the CBI said.

Earlier in the day, the agency raided multiple locations owned by Videocon Industries and NuPower, a CBI source said.