Twenty-seven-year-old James Edward Armstrong was arraigned Thursday in the fatal shootings of Feliz Pizarro in 2009 and Larry Douglas Carter last year.
He's already charged with killing Eric Caldwell in 2007.
Chester police say Armstrong had been the focus of the investigations for a long time. They say Armstrong killed the 19-year-old Pizarro during a pickup basketball game and the 33-year-old Carter outside a housing development.
Armstrong has been in custody since August in Caldwell's death. A phone message left for his attorney in that case was not immediately returned Friday.