I cannot give much detail on the specifics of the issue that I am dealing with for various reasons, but it involves a person who is convinced that someone close to them has been spying on them using their own computer's webcam. I have scanned the machine thoroughly and checked it for spyware, malware and the like, as it was infected when it came into my possession. None of the "standard" tools for removing spyware, viruses and the like came up with anything other than a keylogger.
I haven't cleaned the PCs because I want them to remain "as-is" should they need them in their current state later - but I need to either verify their claim or show proof that will put them at ease in regards to being spied upon using their own webcam and/or online accounts. I've been researching software that does this sort of thing and what I'm concerned about is that the software is obfuscated and hard to detect via normal means. Most of the tools that I have read about advertise this. the question is: how do I find these programs that are supposed to remain hidden? I've got to figure out if this is paranoia or a legitimate concern.
It should be noted that I am very experienced in the hardware/software aspects of PCs, both hardware and software related (I own a PC repair and support business)...while I've worked with many different situations in the past, this is my first experience in this particular area and I'd like to make sure it's a job done right. I'd rather ask the question and get a "nothing can be done" or "you're doing it wrong" than never ask and miss something because I was overconfident.