OK, when you get to the casino, you see an elephant in a cage and a trainer.

Cast the tracks on the ground to the right of Warrick. You can examine the elephant but find nothing. He's just an elephant.

There's a barrel that has been moved in the corner - you can't open it without a warrant. Wave your heat sensor over it out of curiosity. There's a body in there!! That was sort of spooky :) Now you can open it up.

look at the mouth - there are chips in the mouth.
Use gloves to grab the chips
hips - stained, use adhesive tape it
also grass on legs

Now talk to the trainer.

any cars? dinner hour ago
barrel? owned by casino
suspicious ? everyone. but nothing out of the ordinary

Head back to the morgue!

CSI Crime scene Investigation Walkthrough