Although I liked cast & movie - one scene makes no sense to me

SPOILER

OK - U have the cop who dearly loves Hopkins wife - & when he finds out Hopkins killed her - HE HATES HOPKINS GUTS.

He attacks Hopkins as brutally as possible when he 1st finds outs in Hopkins house.

He attacks Hopkins in court & once again has to be pulled off of him.

Then he is willing to manufacture evidence so he will be found guilty.

Then when Hopkins is found Not Guilty due to lack of evidence, the Cop commits suicide in the courthouse. I don't buy this.

What I do buy is that the cop commits Murder (of Hopkins Of Course), then he commits suicide. He is not going to just let Hopkins off the hook for killing the love of his life & then commit suicide when it is also so easy to kill Hopkins 1st.

By the way - near the end of the movie Hopkins says to Gosling....paraphrasing...And He sat through the whole damn trial with the murder weapon on his hip.

Are cops who testify at trial allowed to have their gun on their hip when they do so?

I'm curious as to what others think.