Two days after three blasts rocked the city of Mumbai killing 18 people and injuring 131, the Union Home Secretary RK Singh on Friday (July 15) said that the CCTV footages procured from the three blast sites -- Dadar, Zaveri Bazar and Opera House -- are being probed thoroughly. Though he did not divulge much detail on the blast probe, the home secretary hinted at a possible email trail that is being investigated.