Murder Mystery

I've recently seen a movie on HBO, that I don't know the name of. A famous man gets assassinated, and detectives try to find him. They find that he has apparently assassinated six other people before this one. He escapes to New York, so the detectives fly on a plane there as well. They manage to find pictures of him going through immigration through the CCTV cameras. He's actually in a gym now, and the detectives come to warn the next suspected victim, as well as give help from him. They manage to find him and it goes into a gunfight.