+0
1: There's a tunnel.
2: Who dug this tunnel?
1: Their rotting bodies were found underground? (In that tunnel?) Gisborne locked them in,
the whole force. All the soldiers?
+0
Madhulk1: Their rotting bodies were found underground? (In that tunnel?)

Presumably so: they were locked in the tunnel and died there. (I don't quite understand the question mark. From what follows, it seems that the speaker already knows the circumstances.)
Madhulk
the whole force. All the soldiers?

I assume it means the whole band of people who were involved in digging the tunnel. If they were soldiers, then yes, all the soldiers.
Comments  
Thanks, Mr Wordy! The question mark is my common mistake. Sorry.