OK, I'll bite.
I know Brad (at least, before he moved to NC). He's not a "computer" expert, never has been. He would show off pictures of the telephone systems he built, for example photos of miles of cat cable routed in a single room making hundreds (maybe thousands) of connections within that room, all done by him. He was very proud of these kinds of photos, where most of us would look at them and not really know what the photo was about or why he was so proud about it.
He had knowledge in a very specific area that also dealt with digital data. While his career path may have brought him specific knowledge, it did not bring him knowledge about everything to do with computers, and certainly not every detail of the Windows OS or how broswers record data.
He got sloppy while angry enough that his mind led him to want to kill his wife. Or there was a massive conspiracy. One of these last two statements is true.
Did he specialize in Networks and Distribution Systems? I suppose maybe I've been giving him too much credit. I've been thinking of computer science degrees as they were a decade or so before Brad completed the degree. I just checked the current degrees and see that they are split into several departments, including Networks, whereas when computer science was a newer field, it meant having a really good understanding of the big picture and especially code. Is it possible that he relied on others (colleagues?) to bring him up to speed on the capabilities of computers, and that he made a mistake in terms of thinking that some computer activities could never be detected? That seems like a really dumb mistake to make. That is, it seems to me that even a person with little knowledge of computers knows that if someone wants to find something on a hard drive, they can.
It's reminds me of Scott Peterson telling police that he was fishing in the SF Bay when his wife vanished, and four months later she was found on the shore. His mother once said to him that not even he could be so stupid as to alibi himself at the location where he put his wife's body, but he was that stupid.
I've noticed that the quality of degrees has gone downhill a lot in the last decade or so. I was asked to review content written by a BComm graduate a couple of weeks ago and he had errors with singular/plural, tenses, and randomly placed commas. For example, he wrote a phrase like "big, red, shoes." I suggested that he removed the second comma, so he removed both. Then I suggested that he add the first comma again. I couldn't believe that someone with a BComm didn't know how to write. Given that, I suppose it's possible that someone with a Comp Sc degree doesn't fully understand computers.