Rudy Giuliani, who served as mayor of New York City from 1994 to 2001, mourned the death of former New York City Police Department Commissioner Bernard "Bernie" Kerik on Thursday, describing the grief of losing his "best friend" and a "true patriot" as "inexpressible."Kerik died at 69 years old "after a private battle with illness," according to FBI Director Kash Patel. Kerik and Giuliani were prominent figures during and after the Sept. 11, 2001, terrorist attacks in New York City due to their leadership roles in the city, and they quickly became close friends."On September 11th, Bernie Kerik and I saved