New Delhi, May 15 -- Income tax authorities are investigating discrepancies detected in the permanent account number held by Rujira Naroola alias Rujira Banerjee - wife of West Bengal chief minister Mamata Banerjee's nephew and TMC MP Abhishek Banerjee - which she apparently procured as an Indian citizen despite having a Thai passport, three government officials with direct knowledge of the matter said.

The home ministry has also been asked to investigate the Overseas Citizenship of India (OCI) card issued to her and her friend, Menka Gambhir, the officials added, asking not to be named. The finance ministry (which oversees the tax department) is the latest to step into what has become a political slugfest between the Trinamool Congress an...