SEATTLE, WA (MyBellinghamNow.com) – A ghost gun was among three weapons Seattle Police recovered from the scene of Sunday evening’s deadly shooting at the Seattle Center.

Police Chief Shon Barnes told a news conference Tuesday that “a ghost gun is an untraceable weapon that lacks a serial number. They are typically homemade and illegal.”

He said this was the weapon found on the 15-year-old suspect who remains in custody.

Officers also recovered two other handguns from the scene, one of which apparently hadn’t been fired. They found 14 shell casings from two different caliber weapons.

A 19-year-old man who was one of three people killed is also believed to have been a shooter.

Barnes said they continue to look for others who may have been involved and are not limiting the search to just a third suspect as has been widely reported. They’re also asking that a man who was treated for an apparent gunshot wound at UW Hospital to contact them in hopes that he may have information.

The toddler injured in the shooting was discharged from Harborview Medical Center Monday evening. The two-year-old was the last person injured in the shooting to be hospitalized.

KOMO News identifies the other two people killed as 56-year-old Ashley Whitehead and 44-year-old Carlos Israel Sanchez Villalba.

Except for the 19-year-old man, all of those injured or killed were innocent bystanders caught in the crossfire of the suspected gang shooting.