Police say preliminary ballistic testing does not show that bullets recovered from two bystanders killed during a shootout at a crowded Seattle food festival last weekend came from the gun of a 15-year-old arrested at the scene. In court documents filed Wednesday, authorities state that the bullets recovered from the deceased bystanders do not appear to match the weapon the teen was seen firing.

Multiple outlets report that the testing is part of an ongoing investigation into what happened during the incident, which took place at the festival on Sunday. Police also characterize the shooting as connected to gang violence, according to coverage in The Guardian, though they have not publicly identified who may have fired the fatal bullets.

The teen was arrested at the scene and is described as having used an untraceable “ghost gun” in some reporting, but the central point confirmed across sources is that the recovered bullets do not appear to have been fired from the teen’s gun based on preliminary analysis. Further investigation is expected as authorities determine the source of the bullets that killed the two bystanders.