An irate driver accused of stabbing an on-duty San Francisco Recreation and Park Department ranger Sunday morning is behind bars and facing more than just attempted murder charges. Police say the ranger spotted 39-year-old Ajmal Amani yelling at other drivers and followed him onto the Central Freeway where Amani crashed into the center divide at Seventh Street. The ranger stopped to assist and got stabbed in the process, but witnesses were on hand to help detain Amani until police arrived. Amani was treated for unknown injuries at a local hospital and is under arrest on suspicion of attempted murder, assault, purchasing a stolen vehicle, and carjacking. The ranger was treated and released at the scene.