I have to say, I'm not convinced by this. If they suspected the ex-wife (as it was clear they did for some time), it would make sense that they might think she had his laptop. They might remember a time where he let her use it etc etc... They might even slightly embellish the truth to cast suspicion on her more. It's natural, if you believe someone is in the wrong, to project even more guilt on them than is evidenced.
Also, until we hear otherwise, I really think the ex-wife should catch a break.