The Calcutta High Court on Thursday asked CBI to file a progress report within four weeks on the disappearance of Nicole Tamang, prime accused in the murder of Gorkha leader Madan Tamang. The CBI informed the court that it has already taken up investigation into Nicole's disappearance. All India Gorkha League chief Tamang was murdered in Darjeeling on May 21 last year. A division bench comprising Chief Justice J N Patel and Justice A K Roy directed CBI to file the report on its investigation after four weeks. The West Bengal government had told the high court that it had issued a notification on November 26 last year handing over the investigation to CBI.