Murder Court Case Events and Dialogue?

First of all, you have to determine where the court is being held. US courts are very different from British courts (Not to mention other courts.) To top it off, the state where the court is being held can matter a lot also. If you have a day or two, go to your local court and watch a few hearings, that should help you. Hearings are open to the public and you don't have to watch a murder trial to get the idea.

If you get a good feel for what your local court hearings are like and don't mention what state the trial is in, you should be able to get away with imagining what happens in a real murder trial. You can also read court transcripts. There are a lot of good mysteries that have the courtroom as a setting. Perry Mason novels are a fair indicator, but there are a lot of novelists who write legal thrillers. (You could get a lot of them from your public library as a starting off point.

If you are really serious about what you are doing, you might want to chat with a lawyer about Rules of Evidence and court proceedings. It will cost a little money, but you can claim that as a business expense on your Income Tax.

There are lots and lots of specialized books specifically for fiction writers on just this kind of thing: how courts work, how the police work, how emergency rooms work, etc. Your library probably has some of them, and if not, can probably get them for you by interlibrary loan. Get some of them and read them.

You can also buy them from Writer's Digest magazine and other publishers.