It is my "understanding" that OS X over-writes the files immediately when they are deleted. So unless one has a special program (such as Data Recycler) installed prior to the delete, or calls in NSA or the like, the files cannot, for all practical purposes, be recovered.
But, I have no real source of my "understanding", so I truly do not know if I am correct, sorta but not exactly correct, have been listening to idiots, have sampled a wee bit too much of the cooking sherry, or the ravages of time have (finally) taken their toll on my synapses.
Any enlightenment most appreciated.
Harv