Police has now turned to dump data - collection of mobile numbers operating in the area when the incident took place - to identify the assailants.
"Several leads which we had been working in the last 48 hours have led into a dead end. We are now looking for new clues," said a senior police official investigating the case.
They have asked all mobile operating companies to provide their data regarding the numbers active in an around Kamla Nagar area.
Investigators believe that the numbers which would be found active in both these spots simultaneously may lead them to the assailants.
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As many as 10 teams are working to crack the case, including those from the Special Cell and Crime Branch are looking into the case.
Meanwhile, police is also going to issue an advisory to follow the Standard Operating Procedure to all cash replenishment agencies.
Scientific Systems Management Services, the company involved in this case may also face police action for not following the SOP.