The couple's visit to Thiruvananthapuram, where she was hospitalised at Kerala Institute of Medical Sciences (KIMS) for three days before returning to Delhi on Wednesday is also under police scanner.
Police is also planning to seek all the treatment details of Sunanda from KIMS.
Doctors at the AIIMS will submit a preliminary report tomorrow on their post-mortem findings to the SDM. After the postmortem, doctors yesterday had said that Sunanda died a “sudden unnatural death” and her body bore several injury marks.
Police sources said that it could be a case of drug overdose.
A number of private staff of Tharoor also recorded their statement before the SDM.
