Clues in the Thicket

This is part of The Terokkar Mana Bomb quest chain.

Want to investigate a mystery? Here's one now!

Objective
Investigate the Strange Object next to the Broken Corpse to determine what might have befallen the Cenarion Thicket. Then return to Earthbinder Tavgren just outside the thicket in Terokkar Forest.
 * Strange Object examined

Description
I have no idea what killed all of the druids here. I've been away for a couple of days on a survey of the Bone Wastes to the south.

Please, you must help me to uncover what's behind this horrible tragedy. Go into the thicket and look for a clue that might reveal something to us. When I was in there briefly, I could have sworn I saw a dead Broken and a strange object next to him.

And don't worry about Treelos - he might have been driven insane by what happened, but I think he's mostly harmless.

Progress
Have you discovered anything yet?

Completion
So, I was right. That was the corpse of one of the Broken? And you can confirm that there was a strange object on the ground next to him?

This doesn't make any sense. What would one of the Broken be doing here? And what is that thing it had with him?

Is it was caused all of this death?

Rewards

 * You will receive:

Gains

 * 8300 XP
 * 250 reputation with Cenarion Expedition