DENVER (KDVR) — One person was killed in what police are calling an “accidental death” involving an explosive in Aurora.

The Aurora Police Department confirmed to FOX31 that officers were investigating an accidental death. However, police initially said the death involved some kind of homemade explosive, but they later said they were not sure if it was homemade or possibly purchased from out of state.

Officers said they received several calls at 12:49 a.m. about “a suspicious occurrence involving an explosion at Grandview Dog Park.”

FOX31 received several tips from viewers on Thursday about a loud boom. Many residents took to the Nextdoor app to share what they heard.

Juan Molina told FOX31 reporter Vicente Arenas that the sound woke him up.

“At first I thought something had exploded inside the house the furnace or something,” Molina said.

Arenas asked if the house shook from the explosion.

“Oh yeah,” Molina said.

Molina climbed up on his roof to see where the noise had come from and heard noises from the park.

Deadly explosion at Aurora dog park (KDVR)

The park is located at 17502 E. Quincy Ave., northwest of the Quincy Reservoir in Aurora.

“At first I thought it was a guy (saying) ‘help her’ or something like that and they were running,” Molina said.

According to police, a 42-year-old man from Strasburg was killed when the device exploded. Investigators said the man had traveled to Aurora with two other people to visit food and beverage businesses.

Just before 1 a.m., the group went to the dog park with what police said were several large, commercial-grade fireworks. Initially, police said they appeared to be homemade, however, an update from Aurora police said it is unclear if the fireworks were homemade or purchased out of state. Police told Arenas that four additional explosives were found at the park.

Officers went to the man’s Strasburg home and did not find any evidence of explosive-making activity and did not find any additional fireworks. The Bureau of Alcohol, Tobacco, Firearms and Explosives was working with the bomb squad to determine what the device was, according to Aurora police.

Estrella Bello also lives near the park and told Arenas she jumped out of bed, too.

“It just felt like such an intense, like, bam! My heart instantly like, ya know, stopped because I have my kids and stuff,” Bello said.

The park was reopened to the public around 3 p.m. Thursday.

Anyone with additional information on this incident is asked to contact Metro Denver Crime Stoppers at 720-913-7867.