Did you have the nice notice from TSA saying they screened your bag? That will help point you in the right direction. The TSA has a response line for items missing from baggage.
It's also most likely (though not guaranteed) that your items were misplaced or stolen in your first point of departure (OMA). DTW would have just transferred your bag and LAX would have just delivered it to the belt. Of course, stranger things have happened.
Sorry to hear about your loss. I hope these items turn up soon and in tact!
-RM