What type of crab is this

[rattslik]

I saw this in my tank last night and it wasn't moving. I woke up this morning and I saw it has moved. I put my hand in the tank so see if it was alive. To my surprise it wasn't. I know there is a bigger crab In the tank but otherwise I don't understand what killed it.

 

[Louiemiller9]

I saw this in my tank last night and it wasn't moving. I woke up this morning and I saw it has moved. I put my hand in the tank so see if it was alive. To my surprise it wasn't. I know there is a bigger crab In the tank but otherwise I don't understand what killed it.

Looks like a (hitchhiker)gorilla crab.... I’m not an expert though