The accused, Mohd Parvez, who is in his early 30s, was arrested on September 13 by the local police but after it was found that he had visited Pakistan a few times, the matter was transferred to the Special Cell for probe, they said.
A woman colonel filed a police complaint in Dwarka, alleging that she had been receiving morphed and obscene pictures through WhatsApp from two unknown numbers.
She was threatened that if she did not speak to the sender of the messages, the pictures would be circulated on the internet, the police said.
After she blocked the two numbers, the woman colonel's daughter started receiving morphed pictures and messages from the Facebook profile of a woman, they said.
The person sending the pictures and messages asked the woman's daughter to speak to the sender and threatened her with uploading the pictures on social media.
During his interrogation, it emerged that he had visited Pakistan and had made SIM cards available to some Pakistani nationals. It was suspected that he is linked with the Inter-Services Intelligence (ISI), the police said.
He was found to have suspicious antecedents and is being questioned by the Special Cell sleuths in connection with the matter, they said.
It is suspected that he was threatening the woman colonel since he wanted to extract sensitive information from her, an angle that is currently being probed.
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