Images shows investigators sifting through the rubble from a downtown Nashville blast on Christmas Day
Anthony Quinn Warner, 63, the suspected bomber, is believed to have purchased chemicals with credit card
The Friday explosion came from a white RV parked outside the AT&T building on 2nd Avenue at 6.40 am
The explosion injured at least eight people and caused severe damage to the city's downtown area
On Monday Memphis FBI released a new photo of Warner where he appears to be leaning out of the white RV
Human remains found at the scene of the explosion match those of the man identified as the bomber