Why CBI wants to grill Sandip Ghosh, 5 others with lie-detector

Sandip Ghosh, ex-principal of RG Kar Medical College, and four colleagues of a junior doctor, found raped and murdered, agreed to polygraph tests following a CBI request. The CBI aims to resolve discrepancies in their statements. The victim’s parents allege evidence destruction and demand justice, expressing frustration with the investigation’s progress.