NASHVILLE (Tennessee) • US investigators are rushing to piece together what officials described as an elaborate jigsaw puzzle, chasing more than 500 leads to identify the culprit and the motivation behind the Christmas Day explosion that rocked Nashville, Tennessee.
On Saturday, local police and agents from the Federal Bureau of Investigation (FBI) and US Bureau of Alcohol, Tobacco, Firearms and Explosives searched a two-storey, red-brick house in Bakertown Road in Antioch, 18km south-east of Nashville, paying particular attention to its basement.
A motor home, parked on a downtown street of Tennessee state's largest city, exploded at around 6am last Friday moments after police - responding to reports of gunfire - noticed it. They heard an apparently computer-generated female voice from inside reciting a minute-by-minute countdown to an impending bombing.
The blast rippled across several blocks, blowing windows and even causing one building to collapse, and it left Nashville rattled and perplexed. About 40 buildings were damaged and at least three people were injured, with the streets largely empty at that hour.
Parked cars and trees were blackened and an exploded water pipe that had been spraying overnight covered trees in a layer of ice.
The authorities said the blast had the potential to inflict enormous carnage had it detonated at a time other than early on a quiet holiday morning and without the warning that led police officers to clear away as many people in surrounding buildings as they could.
"All the windows came in from the living room into the bedroom. The front door became unhinged," Mr Buck McCoy, who lives on the block where the blast occurred, told local TV station WKRN.
"I had blood coming from my face and on my side and on my legs and a little bit on my feet."
Officials on Saturday declined to name a person of interest in connection with the explosion, but CBS News reported that the investigation has homed in on 63-year-old Anthony Quinn Warner, who recently lived at the Bakertown Road address, public records showed.
According to a document posted online, on Nov 25, he signed over the property to a woman in Los Angeles at no cost to her.
The document was signed by Mr Warner, but not by the woman.
Google Street View images of the house from last year show what appears to be a white motor home in the driveway. Neighbours told WKRN that the recreational vehicle had been parked there for years and is now gone.
Some US media outlets reported on Saturday evening that the bomber may have been killed in the blast, but the authorities have not officially confirmed anything.
Possible human tissue has been found amid the debris.
Police said the blast was "intentional" but the motive remains unclear and FBI behavioural analysts were involved in the investigation.
"The damage is shocking and it is a miracle that no residents were killed," Tennessee Governor Bill Lee said on Twitter.
He 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.
One of the major lines of inquiry was whether there was significance in the location of the blast: on a downtown street in front of an AT&T transmission building.
The explosion created significant damage to the facility, causing widespread repercussions to telecommunication systems in Nashville and beyond.
The Federal Aviation Administration temporarily halted flights out of Nashville International Airport because of telecommunications issues caused by the blast. It also labelled the skies within around a kilometre or so of the blast "national defence airspace", meaning pilots are prohibited from flying overhead without authorisation.
On Saturday, shoppers at some retail outlets had to pay with cash or cheques, as sellers could not access credit card systems.
NYTIMES, REUTERS, AGENCE FRANCE-PRESSE