You are correct; the sentence implies an "if" and is a conditional statement. However, be careful to distinguish between dialog (which can accurately capture how people speak) and exposition. Grammar rules aren't held fast to in dialog, but they are (generally) elsewhere.
However, you cannot say, "I will kill you," because that removes the condition from the statement completely. The original sentences states that the man (assumed) will kill the person if (implied) that person touches his bag.
Also, will means that the action is sure; only the time is uncertain. If the speaker said your second sentence, the time between saying it and killing the person could be seconds or days, but it leaves no doubt that the speaker will do his utmost to kill the other person.