Police previously alleged that David Shanton fired a shotgun at a police officer who was responding to the robbery and later held a mother and her daughter hostage at gunpoint for several hours while he eluded police.
The federal indictment further alleges that David Shanton used a gun during an attempted robbery of the Susquehanna Bank branch at 1326 Salem Ave. on Nov. 24, 2007.
He had the deputy's service weapon taken during the October robbery during the November attempted robbery, Hagerstown Police Sgt. Paul Kifer has said.
Washington County Circuit Judge W. Kennedy Boone III said he was reluctant to waive Shanton back to juvenile court, but did so in light of the "totality of the circumstances."
"He was in to this up to his eyeballs," Boone said during Monday's hearing.
Kevin Shanton physically forced someone to sit during the bank robbery, and he later pointed a handgun at a woman and her daughter after the men forced themselves into the woman's apartment, Boone said.
The mother and daughter were held hostage in their Manor Drive apartment for about six hours, police have said.
Boone called Kevin Shanton's actions "totally reprehensible" and said he had concerns about sending his case back to juvenile court.
"I had concerns. The seriousness of this charge and whether he's a threat to public safety, I don't know," Boone said.
As a condition of the waiver to juvenile court, Kevin Shanton agreed to testify against his grandfather for any state or federal prosecution. He also must admit his involvement in a conspiracy to commit armed robbery, according to the agreement between prosecutors and the defense.
Deputy State's Attorney Joseph Michael said in court Monday that the elder Shanton would not have been caught without Kevin Shanton's cooperation.
"But for this defendant, that robber would still be free," Michael said.
At the juvenile hearing, the state and defense will recommend that Kevin Shanton be released to his mother. The judge presiding over that hearing may order that Shanton be placed in a juvenile facility until he is 21.
Kevin Shanton remains free on a $10,000 bond pending his appearance in Washington County's juvenile court.