The boy is being charged as an adult for first-degree reckless homicide and is being held on $50,000 bail. If convicted, he could face up to 60 years in prison.
It was the deadliest US school shooting in almost a decade, and many children were wounded.
Multiple shooters exited a vehicle in the Kensington area of the Pennsylvania city and began shooting, firing about 40 shots.
Tony Payne of Tunnel Hill, Georgia told Capitol Police he had come to deliver documents to the US Supreme Court.
Jurors determined Thursday that Nikolas Cruz should be sentenced to life in prison for a 2018 school shooting in Parkland, Florida, that killed 17 people.
The Israeli later claimed the Thai translator at the police station "convinced him" to drop all charges against the officer.
The massacre in Thailand is one of the world's worst child death tolls by a single killer in recent history.
The New York State Jewish Gun Club, a Rockland County-based firearms club, funded and put together the lawsuit, which was filed on Sept. 29 in the Southern District of New York.
Robert Crimo III, the gunman who killed 7 people and injured 30 at an infamous 4th of July shooting, pled not guilty to the charges.
Uvalde law enforcement officials have been roundly criticized for their handling of the rampage and especially for waiting more than an hour before confronting Ramos.