What Does Quran Say About "Spying"

[Osman]

Salaam Alaikum brother Joseph,

What does Quran say about "Spying"... if its done as a preventive measure against a possible conspiracy?
I am suspicious of my friend... i think he may be conspiring against me... as he has done that in the past too. Can i spy on him? Would it be morally justified?

[Sardar Miyan]

Salam Bro Osman In my opinion you are entitled to spy for your safety particularly when your friend has tried to harm you in the past. Your safety is the priority.

[Wakas]

Perhaps you will find this helpful:

49:12
O you who believe, you shall avoid much suspicion, for some suspicion is sinful. And do not spy on one another, nor shall you backbite. Would any of you enjoy eating the flesh of his dead brother? You certainly would hate this. You shall observe God. God is Redeemer, Merciful.