Question

According to Jewish law (aside from state law and the law of the land), is it permitted to record someone secretly in ordinary day-to-day situations when I suspect that something is being done deceitfully or outright improperly? I’ll give a few different examples, and maybe the ruling is different in each case, but just to frame the question: for example, to check whether someone I considered a friend is badmouthing me behind my back and also causing clients to leave me; or whether the babysitter leaves the baby crying for a long time; or whether two employees are planning together to cheat me; or whether the children are listening to music I don’t allow when I’m not home. For that matter, if the problem is the extra information included in the recording beyond the specific thing I want to check, then I could send it anonymously to some freelancer who would listen and answer whether the recording provides answers to questions A, B, and C, and then cut out for me only the relevant parts. Thank you very much, honorable Rabbi. Of course, I’m not talking about systematic recording over time in order to fish for problems, but when I have a reasonable suspicion, to record a little as possible in order to check it. On the one hand, it seems at first glance like something very nasty to record someone without his knowing, because he didn’t want to tell me, and everyone has things they don’t say to someone else—and I too would be embarrassed if everyone knew exactly what I said to each person and about each person; unfortunately I’m not some pure innocent saint. But on the other hand, if it seems to me that I have a right to know this information and I have no other way to obtain it, then what—just because I’m blocked, the cheaters should have a field day? That doesn’t smell right either. Thank you very much, Rabbi.