Legal Question in Civil Litigation in Louisiana

Re: If I was mailed a suppena to go to court do I have to go

Yes, you do have to go.

Unless the defendants plead guilty, the government has to prove to a jury (people who weren't there) that these men are guilty beyond all reasonable doubt. Since juries come from the general population, they can include people who don't believe police officers (in which case you are there to complete the witness list). Also, sometimes a witness, even a police witness, doesn't present well in court, other witnesses are necessary to fill those gaps. Most importantly, good prosecutors (and other good lawyers) want to make sure that the whole story is told in the manner best for their client. The prosecutor's client is the State. As a resident of the State you probably wouldn't want the DA to be sloppy or lacking in effort.