Who is Joe Bellini from Cathedral and what is their importance?

Captain Joe Bellini is a member of the New York City police department. He is a part of the decision making force at the cathedral, and he has a specially trained team with snipers ready to assault the cathedral, if necessary. Over the course of the stand-off, Bellini is told he must sign a paper for the city saying that an attack is in the best interests of the hostages. He agrees to think about it. He later develops a good plan for the assault that is based on the blue prints of Stillway. In the end, Bellini is killed by sniper fire from Leary.