Pizarro protected Atahualpa.
He was allowed to keep his wives and to conduct matters of the empire from his cell in Cajamarca, Peru
This kind of closeness and friendship between the two leaders wasn't accepted by Pizarro's men.
They grew uneasy and frustrated as gold was nowhere to be seen, at least not to the extent they've all envisioned.
Their search for Eldorado took them even to the Amazon jungle, but gold continued to elude them.
Atahualpa on the other hand, knew his life depended upon a delicate balance between what to say and how much to reveal regarding to it.
By saying it all he knew he wasn't going to be needed anymore, therefore becoming expendable to Pizarro.
Pizarro finally menaced Atahualpa with execution.
In exchange of his life and freedom, he would have to fill up a 50 sq. meters room with gold.
Pizarro never kept his promise and executed Atahualpa nevertheless...