CBI is collecting DNA samples of all persons associated with the postmortem of teenager Aarushi Talwar, whose murder had hogged national focus, to find the identity of the woman whose vaginal swab was sent to CBI for forensic tests. The CBI team probing Aarushi-Hemraj double murder case, which has been working overtime in re-working the missing links of the case, decided to collect the DNA samples of doctors and technical staff of the hospital where the postmortem was done. The decision to do this was taken after it came to light that the vaginal swabs drawn from the victim were substituted with those of an unidentified woman. This was found during the tests conducted by the Centre for DNA Fingerprinting and Diagnostics in Hyderabad.<br/><br/> Aarushi's parents Rajesh Talwar and Nupur Talwar, who are to be subjected to narco analysis test following a court direction, may also be questioned in connection with the bungling.