Sources in the IT department said the exercise by its investigation wing was in continuation of the earlier searches carried out at the shell companies (entities which serve as a vehicle for business transactions without themselves having any significant assets or operations) related to Purti group in Mumbai.
"We are verifying the addresses of the companies, the nature of the business and (whether) do they really exist," an IT source said.
According to the sources, the inquiries followed "certain doubts" raised by the Pune branch of the department, which asked its Mumbai counterpart to inquire into those.
"If need be, we will record the statements of the persons whose names are shown as directors of these companies," the sources told PTI on condition of anonymity.
Gadkari, who was asked by the Income Tax department to appear before it yesterday in connection with the probe into alleged dubious investments in Purti group of companies, had sought more time to present his case.
Citing his preoccupation with party work as the reason for his inability to appear before the tax authorities, he sought fresh time, sources had said yesterday.
They said he has been asked to appear on February 1.