Chattin has been linked to seven armed robberies since Oct. 31, when police say he was allowed to go trick-or-treating, but robbed a pizza delivery man instead.
Police say 16-year-old Alexander Grier was linked to two robberies with Chattin.
Both are charged with first-degree robbery, conspiracy and wearing a disguise during the commission of a felony and weapons charges. Chattin faces additional charges, including attempted robbery and assault.
Both are being held at the New Castle County Detention Center after failing to post bail.
