The arrest of IAS officer M Sivasankar, the former chief secretary to the Chief Minister, is being seen as a massive setback to the CPI(M)-led Kerala government.
The main accused in the case, Swapna Suresh and another former employee of the UAE consulate named Sarith were arrested in July for using forged papers to claim diplomatic immunity and smuggling gold from UAE.
Swapna Suresh has also admitted before the probing agency that the private meetings between Vijayan and the UAE diplomats were held at CM's official Vijayan's official residence in Thiruvananthapuram.