NASHVILLE, Tenn. (WKRN) — The mid-1960s classic “Downtown” by Petula Clark played from the RV parked in downtown Nashville prior to the explosion that damaged more than 40 buildings and injured at least three people Christmas morning.

“What I remembered was ‘downtown, where the lights shine bright,’” Metro Officer Tyler Luellen said of the song playing, as he and his fellow officers worked fast to evacuate people in the area of Second Avenue North and Commerce Street.

Officer Luellen was one of six officers who spoke to the media Sunday morning about their efforts to clear the area around downtown Nashville, as the RV played messages, including a countdown, warning it would detonate. A bomb inside the RV exploded around 6:30 a.m. Friday, leaving behind a trail of destruction.

The officer said he looked up the song later and discovered it was “Downtown” by Petula Clark, the chart-topping song that begins, “when you’re alone and life is making you lonely, you can always go downtown.”

During the media briefing, Officer James Wells revealed the RV had surveillance cameras on it.

“There was also cameras on the RV like surveillance cameras above the mirror,” Officer Wells explained. “It felt like whoever was behind it was watching us.”

Officer Wells suffered temporary hearing loss as a result of the blast and Officer Luellen was knocked to the ground. Three other people were transported to area hospitals with injuries that were not considered to be life-threatening, according to Metro police.

Law enforcement sources told ABC News and the Associated Press Saturday that a 63-year-old Antioch man was considered a “person of interest” in the bombing. His home on Bakertown Road was searched by multiple agencies, but investigators had not commented further.

Human remains found at the scene of the bombing had not been positively identified as of Sunday morning, ABC News reported.

The investigation into the blast remains ongoing.