The Central Bureau of Investigation (CBI) questioned the sister-in-law of Trinamool Congress MP Abhishek Banerjee in Kolkata today in connection with a coal pilferage case. The questioning lasted for three hours at Menaka Gambhir's residence. Menaka is the sister of Banerjee's wife Rujira who was summoned by the agency yesterday. <br />''<br />''In her reply today, Rujira told the agency that she was unaware of the reason for being called for questioning or the subject matter of the investigation. However, she mentioned that she will be available at her residence tomorrow between 11 a.m. to 3 p.m.<br />'' <br />''<span style="color: #222222;">It may be noted that Abhishek is the nephew of Chief Minister of West Bengal Mamata Banerjee. The CBI officials visited Abhishek's residence yesterday to serve the notice to his wife.</span><br />