Preliminary investigations have revealed that Arpita Mukherjee, known to be a "close associate" of arrested Bengal minister Partha Chatterjee, had been running at least 12 shell companies, primarily for financial manoeuvres, a senior official of the Enforcement Directorate said on Monday.

Documents "supporting the existence of such companies" have been recovered from Mukherjee's Joka flat during search operations conducted on Saturday evening, he said.

ED sleuths also suspect involvement of a few lesser-known actors as well as people from different production houses in Odisha and Tamil Nadu, the official said.

Mukherjee has also acted in several Bengali and Oriya films.

"We have found documents from Arpita's Joka flat which indicated that she was operating several shell companies for financial manoeuvres. We have documents of 12 such companies. There could be involvement of people in Odisha and Tamil Nadu, who, we believe, moved the money," the official told PTI.

The ED is "keeping a close eye" on some people of Odisha and Tamil Nadu and may soon grill them, the agency official explained.

"We are also trying to find out if Arpita has invested in any film production house. We have several documents, files, signed papers to suggest so," he added.

A city court on Sunday remanded Mukherjee in one-day ED custody. She was arrested following marathon questioning at her residence, where crores of rupees in cash and other valuables were allegedly recovered by sleuths of the central agency.