Covert and deceptive means an action has been initiated before the crime has taken place. That is why alshabaab the terrorist group used this method as tool to launch Jihad in Somalia.
That is exactly the signs of takfiiri in Islam. You can not create a crime before the crime took place. You can not call a kaafir to muslim brother. When you are using deceptive and covert, you are actually created the whole crime by yourself. That is exactly why Ibrahim Afghaani was killed in that operation.