First posted 04:41pm (Mla time) Sept 28, 2005 By Nancy C. Carvajal Inquirer News Service A POLICE officer was killed while shooting it out with holdup men inside a passenger bus at the Northern Luzon Expressway at dawn Wednesday, police said. One of the robbers was seriously wounded, but was brought along by his fleeing cohorts. P02 Joel Magbanua was among the 30 passengers of a Baliwag Transit bus when seven men armed with handguns and knives declared a holdup at Burol, Guiguinto, Bulacan. The bus came from Cabiao, Nueva Ecija and was bound for Cubao, Quezon City. Valenzuela police chief Superintendent Billy Beltran said the robbers fired back at Magbanua after he shot one of their companions. They also repeatedly stabbed the police officer.