Lets now look at Muhammad (prophets) fruits of how he dealt with some people, these are true stories taken out of Islamic books like the Sahih Bukhari which is considered Sunnah in Islam.  Any Muslim who denies the hadith is not considered a Muslim and must obey the Sunnah.  These are people who were assassinated by Muhammad's orders by his followers.

Now you tell me what is the motive of a prophet doing this sort of behavior, if Muhammad prophet is a real prophet then why couldn't God  deal with these people on his behalf.