Investigators including police and FBI behavioral analysts searched houses and related properties in Nashville and Antioch as officials identified a 63-year-old as a “person of interest”, an AFP report said. A Nashville residence was frisked as authorities probed the blast that injured several people and damaged dozens of buildings on Christmas.

The Antioch reference came up after a US media report discovered a lead, AFP stated. Investigators are searching properties connected with Anthony Quinn Warne, ABC News reported. The connection has been drawn with relation to the parked motorhome that blared a warning minutes before it blew up.

According to the local media outlets, the bomber may have been killed in the blast, but an official statement is yet to be released, AFP added. However, on examining tissue found at the site, authorities believe those could be human remains.

The police defined the blast as an “intentional act” but the motive remaina unclear, AFP states.

“The damage is shocking and it is a miracle that no residents were killed,” Tennessee Governor Bill Lee said on Twitter on Saturday.

Reports have mentioned that the motorhome was spotted by neighbours outside the residence.

“No one has been arrested, but information developed during the course of the investigation led us to this address,” an FBI spokesman said in an interview with the Nashville Tennessean newspaper outside the home being searched.

Federal prosecutor Don Cochran said the scene was “like a giant jigsaw puzzle created by a bomb that throws pieces of evidence across multiple city blocks.” The investigation included about 250 FBI agents, analysts and other staff, said the agency’s Doug Korneski.

“We have over 500 investigative leads and we’re following up on every one of those,” Korneski told reporters.

“So there are a number of individuals that we’re looking at. So at this point, we’re not prepared to identify any single individual.”

He added, however, that “at this point we don’t have any indication that we are looking for another subject.”

The governor toured the site on Saturday and said he had asked President Donald Trump to declare a state of emergency, a technical move that triggers federal assistance in repairing damage.

“These buildings, many of which are historic, and others will need to be assessed by an engineer for structural integrity and safety,” Lee said in his request.

According to a timeline provided by the authorities, police were called to the area to respond to gunfire at 5:30 am, and officers spotted the motorhome at 6:00 am.

Fifteen minutes later, they heard an audio countdown coming from the vehicle warning of a bomb — interspersed with music — and the need to evacuate.

Police have not said if anyone was inside the motorhome at the time but lauded the officers who arrived at the scene and took quick action.

“Instead of taking it as just maybe a threat and calling in and getting resources, they immediately began knocking on doors, they coordinated the resources to get everyone evacuated and out,” Nashville Police Chief John Drake said.

The motorhome was parked in front of a building for phone company AT&T, causing damage that disrupted telecommunications service in Tennessee as well as parts of Alabama and Kentucky.

AT&T said Saturday that two portable cell sites were operating in downtown Nashville and additional portable sites were being deployed in the region to restore service.