Despite the thief's desperate attempts to escape, the group was able to surround him. Still he wasn't willing to tell them anything about Martin's position. In fact, he said he would rather die than betray him.
"Why did you decide to follow Martin in the first place?" Josh asked. "What did he tell you?"
Since he didn't seem intent on telling them where Martin was hiding, this seemed like a good place to start. Martin was most likely deceiving him, like he'd done to Anthony back in Beach Cave.