Agency sources said CBI had located 33 imported vehicles and handed them over to their owners with an undertaking that these vehicles would be produced before the court whenever required during the probe.
They said CBI is still trying to locate more vehicles, including those in alleged possession of Stalin's son Udaynidhi and former Union Minister M K Alagiri, which have been allegedly imported by Hyderabad-based Alex C Joseph in collusion with a senior intelligence officer of DRI Muruganandan.
The CBI on March 21 carried out searches at various locations including Stalin's house in Chennai in connection with the case.
The CBI action which came within two days of DMK withdrawing support to the Congress-led UPA government at the Centre had evoked sharp reaction from various quarters disapproving of the agency's action.
The CBI had registered a case under various sections of Indian Penal Code (IPC) including criminal conspiracy, forgery, cheating and abuse of official position against businessman Joseph and DRI official Muruganandan besides other unknown persons.