India, Nov. 18 -- Investigators have uncovered that Delhi suicide bomber Dr Umar Mohammad, also known as Umar-un-Nabi, quietly visited his family home in Pulwama just a week before he detonated an explosives-packed car near the Red Fort, killing 13 people, media reports said.

According to NDTV's sources, this was when he handed over one of his two phones to his brother. a phone that would later become the key to exposing his disturbing "martyrdom" video.

Fearing police were closing in on Nabi, too, the brother dumped the phone into a pond near their home.

When investigators tried tracing Nabi's devices, both were switched off- one last active in Delhi, the other in Pulwama.

The phone, badly water-damaged, took days to yield its conten...