Thrust reverser, same as Eqypt Air Flight 990 out of JFK Oct. 31, 1999, southeast of Nantucket Island, a Boeing 767-300 on flight from N.Y. to Cairo crashed into the Atlantic Ocean, killing all 217 aboard.
Flight 587 may end up the worst aviation disaster in U.S. history if more bodies are found on the ground. It's the 2nd worse U.S. aviation disaster in history now at approximately 269 dead.
But you are correct, the tail did fail. The left engine was found .4 mile from the crater, and the verticle stabilizer and rudder .5 mile from the crater (in the water of Jamicia Bay).
This indicates to me that it was the reverser. But the finding of explosive residue could change all this.