Let's preface by explaining that law in Louisiana is different than every other state in the United States. A student in a law school classroom will be told, "Here is the law for our State. Here is the law for most every other State. And then there's Louisiana."
The other 49 states in the United States use an English common law system derived from the British legal system and the Magna Carta. Louisiana uses a French civil law system based off the Napoleonic Code. (That's why Louisiana uses "parishes" instead of "counties.") While most criminal laws are specific to each state, there is something known as the "Model Penal Code" ("MPC") which is fairly universal.