Thomas confirmed the investigation extends to the boy's home, where he apparently obtained the gun — something police acknowledged could lead to prosecution of his parents or other adults who knowingly made it available to the boy. He said he couldn't provide any information as to whether the gun was locked up.
"We're continuing to investigate the weapon and where it was obtained and how it was obtained," Thomas said.
He said they still don't know whether the shooting spree was random or targeted specific individuals.
Sparks Deputy Police Chief Tom Miller said on Monday it was possible charges could be brought against the boy's parents or other adults, but said that would be up to county prosecutors.
Under Nevada law, it is illegal to allow anyone under 18 to handle a gun without supervision. The offense rises to a felony if there was substantial risk the child would use the firearm to commit a violent act. However, the law doesn't apply if the gun was stored securely or if the child obtained the weapon unlawfully.
Washoe County District Attorney Richard Gammick said in an email to AP on Wednesday no case has been submitted to his office regarding the shooting.
"If and when one is submitted we will review the facts and determine if a criminal prosecution is warranted," he said.