About 12,000 law officers stood at attention outside a New York City church where a funeral Mass was held for two policemen who were shot in separate incidents within hours of each other. Busloads of New York police officers, their shields draped with black mourning bands, were joined by colleagues from around the state and from Massachusetts, New Jersey and Connecticut for what officials called the largest police funeral in city history. They stood 10 deep in chilly weather, filling more than six blocks of the Bay Ridge neighborhood of Brooklyn. Hundreds of civilians also stood behind police barricades surrounding the church. Christopher Hoban, 26, an undercover officer from Bay Ridge, was shot in the head and chest last week during a Manhattan drug raid. Michael Buczek, 24, a highly decorated street officer who lived in Suffern, was killed less than three hours later while he and his partner pursued a suspect in Harlem.