In an update to the Seattle shooting that took three lives Sunday evening, it turns out the initially arrested suspect is just 15 years old — and police now are saying there were two other suspects: one who died at the scene and was an acquaintance of the teenage arrestee, and another unknown suspect, the Associated Press reported."Based on the evidence at the scene, investigators believe" the 15-year-old "and one of the deceased engaged in a gunfight with at least one other unknown suspect," according to a document filed in juvenile court in Seattle, the AP said.'I heard bang, bang, bang, and I heard yelling, straight yelling.'Mayor Katie Wilson said at a news conference that the arrested 15-year-old was being held in juvenile detention for investigation of firearms violations and first-degree assault ahead of a Monday afternoon court appearance, the outlet reported.Authorities earlier Monday said they're still looking for an additional suspect but could not rule out the possibility that individual was among those killed, the AP added.“We are trying to identify who that person is,” Seattle Police Chief Shon Barnes said, according to the outlet.Investigators initially believed two suspects were shooting at each other, the AP said, adding that police said late Sunday night it wasn't clear if any of the shooting victims were involved in the confrontation between the two shooters.More from the outlet:The dead were described as two men, ages 19 and 44, and a woman, 56. The four wounded included a 2-year-old boy, who was in satisfactory condition Monday. The others — two men, ages 23 and 27, and a woman, 39 — were discharged, a hospital spokesperson said.CBS News said the shooting took place around 6 p.m. near the Seattle Center, a popular tourist spot that includes the Space Needle and the sports arena that's the home of the Seattle Kraken and Seattle Storm. The news network added that the area was filled with attendees of the annual Bite of Seattle food festival.RELATED: 3 killed, 4 wounded in shooting at Seattle food festival; 1 suspect arrested, the other still on the loose David Ryder/Getty ImagesWitnesses told KING-TV they heard sounds resembling firecrackers and people fleeing the area and diving for cover."I heard bang, bang, bang, and I heard yelling, straight yelling," a witness noted in the KING interview.Adya Sengupta told the station she took cover in the Seattle Armory and that Seattle Fudge brought dozens of bystanders into the storefront to shelter in the event center."Inside the Seattle Armory was crazy; within seconds, maybe 60-plus, people had flooded the doors inside, all running toward that back corner with Seattle Fudge," Sengupta added to KING.CBS News said the federal Bureau of Alcohol, Tobacco, Firearms, and Explosives indicated Sunday night that several of its agents were at the scene and that Seattle police would lead the investigation. The news network added that Washington Gov. Bob Ferguson (D) said the state SWAT team also responded at the request of Seattle police.A candlelight vigil was planned Monday night at the center’s International Fountain, the AP reported.Like Blaze News? Bypass the censors, sign up for our newsletters, and get stories like this direct to your inbox. Sign up here!