NASHVILLE—Federal agents zeroed in on a Nashville home on Saturday and began sifting through at least 500 leads after an explosion rocked the city’s downtown on Christmas Day, injuring three people, damaging dozens of historic buildings, and plunging much of the city into a panic as communications went down.

The vehicle detonated around 6:30 a.m. on Christmas morning in what police have called an “intentional act.” Officers responded to a call that shots were fired in the area, where they found an RV playing a recording warning that a bomb would detonate “in 15 minutes.” The six local officers who rushed to evacuate sleeping residents were hailed as “heroes” for saving the lives of civilians.

CBS News reporter Jeff Pegues reported on Saturday that police had identified a person of interest—a 63-year-old man named Anthony Quinn Warner. MSNBC confirmed that Warner’s home was being searched in connection with the bombing. Authorities declined to confirm any such details at a Saturday briefing, even after the CBS News report, but said they were not looking for “another subject.”

While questions swirled about the circumstances of the bombing, Warner’s neighbors on Bakertown Road were rattled by the sudden police activity and shocked by the idea that he could have been involved in the explosion.

“They are one of the best families that anyone could ever want to meet,” said Bernice Gilley, who said she has known the Warner family since she and her husband moved onto the street 56 years ago.

Like most of the people on this stretch of Bakertown, Gilley and her husband were shocked when the local and federal agents showed up on Saturday morning. Gilley worried that Warner’s mother had fallen or been injured. She told her husband to go check on the older woman, but the agents stopped him and told him that Anthony Warner was a person of interest in the bombing.

The Gilley’s were shocked about that news. “I’m really worried about her still,” Gilley said. “She’s a very good friend.”

One decades-long resident who knew the Warner family didn’t even know Anthony existed before the law enforcement agents arrived and started asking questions.

His current neighbors agreed that Anthony Warner was very quiet. “He is a very private person,” one told The Daily Beast. “As you can see, his whole house is fenced in.”

Neighbors had noticed that the RV had gone missing shortly before Christmas. A few of the kids on the street saw the pictures of the RV online and asked their parents if it could be the same one that Warner had, but no one really believed it was.