[quote=@Midori]
Edit: Is Takeda supposed to be his surname or his given name? I'm confused because he introduces himself as Inspector Hitoshi which is weird because Takeda is a sort of common surname and Hitoshi is a really common given name. 
[/quote]

I intended it to be the other way around. Like if he was American his name with be Takeda Hitoshi, Takeda being the given name, and Hitoshi being the surname. I was under the impression that in Japanese culture people are usually called by their surname (Maybe if you're an elder or someone in a position of respect) so that's why Matsumoto called him Hitoshi, and when Chomei called him Takeda, his given name, he took it as an offense. But then again, I am an uncultured swine, so I could have it all wrong.