It only took jurors three hours to convict Mustafa Ali of first-degree murder.
Ali was charged in connection with the October 2007 shooting deaths of two armored car guards outside a Northeast Philly bank.
But the panel acquitted 39-year-old Mustafa Ali of trying to kill a third guard during the holdup outside a busy mall.
On Friday, jurors will return to hear arguments on whether Ali should be sentenced to death or to life in prison.
Defense attorneys argued that Ali intended only to rob retired police officers Joseph Allulo and William Widmaier but panicked when Allulo started to draw his weapon. Prosecutors said the defendant stalked the vehicle for eight blocks and planned to kill the guards.
Ali, formerly Shawn Steele, served seven years in prison for robbing several banks in the early 1990s.