In a letter to Prime Minister Manmohan Singh, he said the probe initiated by the Enforcement Directorate in September last into the issue was moving at a snail's pace.
The agency had begun the probe on the basis of a letter by Achuthan to the Prime Minister earlier.
In his fresh letter, Achuthan said the Directorate could have found out the truth about the FDI made by Walmart in two days as the company's own records and documents containing relevant information were available in the public domain.
The investment in the services sector had been fully and directly diverted to Bharti Retail limited, the letter said.
