Sleuths from the Central Bureau of Investigation raided the houses of two deputy commissioners of income tax and seized cash, fixed deposit bonds and land documents worth Rs 1.57 crore from their premises on Thursday.

The raids were conducted on the basis of a case registered by I-T against officials of Chennai Customs for conspiring with a city-based private firm and others and sanctioning fraudulent and false refund claims made by the firm and issuing a cheque for Rs 1.19 crore, a senior CBI official said on Friday.

The customs officials had allegedly helped a marine products exporter to reclaim customs duty they had remitted during export saying that they were exporting only insects.

“The exporter and customs officials together changed the food product exports into insects to reclaim the customs duty paid. Customs officials were ‘benefited’ out of the ‘conversion of food products to insects’,” the CBI official added.

According to a CBI official, details of assets worth Rs1.56 crore were recovered from the house of customs deputy commissioner Prem Kumar at Gopalapuram. Over `1 lakh was seized from the house of Rangasamy, in Saidapet.

“Fixed deposits and bonds for Rs 83 lakh, Rs 28.20 lakh in cash, documents of a house valued at Rs 25 lakh besides good quantity of gold were seized during the search from Prem Kumar’s residence,” the official said.

The customs officials helped an export firm for wrongful gain in May-June 2011, the official added. The anti-corruption branch of CBI, Chennai, had registered a case against officials of Chennai customs and others.