In the early hours of Christmas Day, Anthony Quinn Warner parked a motorhome in front of the AT&T network center on Second Avenue in Nashville, Tennessee.

Several hours later, at around 5 a.m., several loud bangs, recognized by locals as gunshots, were heard. Some 5 to 15 minutes later, there were more gunshots, prompting people to call 911. Around 5:30 a.m., a recorded message began blasting from the recreational vehicle, warning that vehicle was going to explode.

A 15-minute countdown followed and then, a massive, fiery explosion.

In short order, the FBI assigned 250 agents to the task of determining who had just bombed downtown Nashville. The investigation focused on Warner, 63, of nearby Antioch, who had an RV in his backyard that looked identical to the one Nashville police identified as the source of the explosion.

Human tissue found at the blast scene confirmed Warner’s identity, FBI Memphis announced on Dec. 27, and U.S. Attorney for the Middle District of Tennessee Don Cochran said he died there.

There’s no clear indication of what may have motivated the attack. Some media reported, based on anonymous sources, that one of the theories agents pursued was whether the bomber attacked AT&T because of fears over government surveillance through the 5G wireless network operated by the company.

But Warner’s neighbors and one of his business clients mentioned nothing about 5G in media interviews. Warner was a quiet, nice “techie guy,” whose most eccentric behavior included placing an antenna on his house and putting up “No Trespassing” signs on his yard fence, they said. The RV can be seen in his backyard as far back as 2007, based on Google Street View images.

It seems clear, however, that whoever was responsible went to some lengths to avoid casualties. Authorities reported three injuries, none of them serious.

Multiple witnesses said they first heard several gunshots between 5 a.m. and 5:30 a.m.

“That woke us up,” one woman told News Channel 5, noting that it wasn’t enough to rattle her, having lived in downtown Nashville for 15 years. But then more gunshots came some 5 to 15 minutes later, based on slightly differing witness accounts. That was enough to prompt the woman to place a 911 call at 5:32 a.m. She was informed that police were already responding to the scene.

She went downstairs and saw through the blinders the RV parked across the street.

As if through a loudspeaker, a recorded message was playing from the motorhome, witnesses said.

“Evacuate now. There is a bomb. A bomb is in this vehicle and will explode,” the message said, as Betsy Williams, the owner of a restaurant across the street from the explosion, told The Tennessean.

That went on for about 30 minutes, the Channel 5 witness said.

Then the message turned into a 15-minute countdown. By then, police were already positioned at both ends of the block, the witness said.

At some point, the 1963 song “Downtown” by Petula Clark was heard playing from the vehicle.

Immediately before the explosion, the message was, “this area must be evacuated now” and then, just seconds before the explosion, the voice said, “If you can hear this message, evacuate now,” as captured in footage from a security camera that appears to be mounted on the façade of the Studio 154 Luxury Hotel just a few yards down the street from the blast.

At least one witness said the gunshots came in identical-sounding volleys, suggesting they were also prerecorded.

The clearest footage of the explosion appears to come from a traffic camera at the intersection of Commerce Street and Second Avenue. It shows two cars parked on the left side of the street and behind them a white object that could be the RV, but is difficult to discern.

The footage shows police officer James Wells walking away from the blast area, seconds before it occurred.

“This might not be politically correct, but it’s my truth. I literally heard God tell me to turn around and go check on [another officer],” he said later during a press conference.

In one piece of footage from further away, a thin line of smoke appeared to be quickly rising from the area before the large plume of smoke from the blast emerged.

The explosion set at least two cars on fire and nearly demolished buildings at 170, 172, and 174 Second Avenue. Photos from the scene show windows shattered and storefronts destroyed in the adjacent buildings as well.

No discernible wreckage of the RV appears in the many images and videos from the scene.

There didn’t appear to be much structural damage to the AT&T building. The company said the blast damaged the building’s power supply, disrupting internet and phone services for its clients. Customers as far as Florida complained of service outages, although most were back up by Dec. 27.

About three feet of water was pumped out of the building’s basement.

Nashville Mayor John Cooper suggested the attack targeted the AT&T infrastructure.

Some media and internet sleuths noticed that Warner had transferred ownership of two houses worth over $400,000 virtually for free to a 29-year-old woman in Los Angeles to whom he has no apparent connection.

One of the properties was transferred on Nov. 25. The woman told The Daily Mail that she wasn’t aware of the transfer.

Warner transferred the other home to her last year. She then transferred it for free to another woman. The home used to belong to Warner’s brother and was eventually transferred to Warner’s mother, who still lives in Tennessee, The Tennessean reported.

Warner, who had lived in Antioch at least since the 1990s, used to own an electronic alarm company, but its license expired more than 20 years ago. Recently, he was doing IT work for realtor Steve Fridrich, who confirmed to WSMV that he had contacted the FBI to provide information about the man.

Warner never shared his political or religious views, neighbors said. He used to own dogs and took good care of them, one neighbor said.