Puppies!

Watch out, little boy!  That's not just a stray dog, it's a stray demon dog!  What made you think it was safe to pet him is beyond me, but I think it may have something to do with your Larry Fine hairstyle.

So it would appear that the most high-tech thing needed to solve a crime, or at least try to prevent one, is the device that everyone has but not everyone uses: the brain.  Glad to see someone on the force has one.  Yup, they couldn't figure it out until they went low, low-tech and used the tools that everyone is born with: a brain and a good pair of eyes (though, some people may argue that both come in varying models with some being more useful than others, but I'm not going to get into that here).

I guess all it took to uncover "The Plot That Nobody Could Solve" was a guy who could read lips and a criminal too oblivious to notice the dashed line from said guy to the offending lips.  Nobody said that criminals were smart, even when they are members of the police force.  (Though, you would think that this tendency towards evil would have been uncovered through the background checks and profiles done to candidates for the force, but hey, these people don't exactly live in the real world, so I'll cut them some slack)  Also, I'm thinking that Shirl may not be as smart as we've been led to believe since she's talking about the plot while standing a few feet away from the people trying to stop it and nab the ones responsible (perhaps someone should tell her that voice scramblers don't work that way.)
Now, now gentlemen, there's no need to shout, especially when the person you've been monitoring, who I assume you don't want to know that you've just uncovered her nefarious plot, is there in the room (doing I'm not sure what.  Making coffee?  Walking around?  Pointing at something?).  But if you're not shouting at each other, then who are you shielding yourselves from?  Or are you talking on your hand phones, ala Inspector Gadget.  I wonder what kind of reception you get on those things.  I mean, he always had some sort of antenna poking out of the thumb.  Perhaps the technology has improved enough that you don't need that now (though why they'd want to have hand phones when they're already in possession of perfectly good wristwatch radios is beyond me.).