The Central Bureau of Investigation on Friday booked former Mumbai Police Commissioner Sanjay Pandey and ex-chiefs of the National Stock Exchange Chitra Ramkrishna and Ravi Narain in a case related to the co-location scam, The Indian Express reported, citing officials.

The scam pertains to allegations of preferential access to the National Stock Exchange’s trading platform that allowed certain brokers to trade before the markets opened. The first FIR in the case was filed in 2018.

Ramkrishna and Narain, both former managing directors and chief executive officers of the stock exchange, have already been booked in the case. Ramkrishna is in judicial custody since March.

The new case is linked to alleged phone tapping of employees of the National Stock Exchange during the period when the co-location scam took place. The CBI has alleged that Pandey had set up a company called iSec Securities, which was used for electronic surveillance of the employees, The Hindu reported.

The fresh FIR was filed on the directions of the Union Ministry of Home Affairs, an official told The Indian Express. Teams of the CBI are conducting raids at 18 locations across multiple cities in connection to the FIR, the official said.

The raids are being conducted at eight locations in Mumbai, including at properties of Pandey, two in Pune, five in the National Capital Region and one location each in Lucknow, Kota and Chandigarh.

Earlier this month, The Indian Express had reported that the CBI is looking into the functioning of iSec Securities set up by Pandey in 2001.

iSec Securities was one of the firms tasked to conduct security audits at the National Stock Exchange between 2010 to 2015, during which the co-location scam allegedly took place. The company did not alert the stock exchange that its servers were compromised, the CBI has alleged, according to The Indian Express.

On July 5, Pandey had also appeared before the Enforcement Directorate for its investigation into a money laundering angle in the co-location scam. Pandey had retired as Mumbai Police commissioner on June 30.