He thinks someone    is a spy
Question

 
I would like to ask an important question. I am suspecting a brother to be a spy. There are many evidences which leads me and many others to this conclusion. Knowing the person, he seems to be a very pious person MAshaa'Allah. However, there were many matters in which he gave us an impression that he is a spy. Honestly, I am very confused. Am I aloud to suspect someone of being a spy? Am I aloud to warn others? What should I do in this case.
Praise be to Allah.The basic principle is that we should think well of another Muslim, unless he does many things that indicate that we should not think well of him. This is what is known as circumstantial evidence or corroborative evidence. If this happens in this person's case, then there is no harm in being cautious around him, because he is the one who has brought it upon himself by his own suspicious actions.
And Allaah is the source of strength.