Police recently carried out searches at seven premises of the firm's directors.
The case was first reported on December 31, 2013 when the Marine Drive police registered a cheating case against Birla Power Solutions Pvt Ltd for allegedly duping a Worli-based businessman of Rs 1 crore by not repaying his fixed deposit investment on maturity.
The case was later transferred to the EOW. So far, 28 investors have approached EOW, saying they have been cheated of a total of Rs 20 crore.