You spot someone that you don’t know, never seen before, don’t know where they came from, looking at you. You ask yourself, “can they do a push-up or a sit-up? Does it look like they bench press? Does it look like they could make a quick dash or jog for a mile?”
All of that athleticism aside, it’s the “look”. Not what they look like but the way they look at things around them. Anyone who has ever stared down the sights of a firearm can spot someone else that has because they have a focused look. They are not merely walking along like normal people simply not trying to walk into something. No, they are the ones with that “hunter’s” look.
Do you see that two hundred pound guy in his mid-30s jogging by and in good shape for his size? You’ve seen him before, right, sometimes with a dog no bigger than a rodent. Now you’ve seen joggers before, but they’re not built like this guy, and if they have a dog in tow it’s generally ten times the size (for example a hound, a shepherd, or a retriever) that that is capable of keeping up with your standard 5-mile jogger. But this guy has a chihuahua. That means he’s DEA. He might have some tattoos that look ex-military, but any ex-military guys would prefer a working-class breed; so is he exercising his wife’s dog? No. The Chihuahua is his search dog.
Sometimes they even mix it up with a female officer, who is in really good shape. She makes it a point to stop and have cordial conversations which were unsolicited. The knee-jerk reaction is to accept it as flattering flirtations, but she is already in a relationship (or so she says) so you don’t find it odd later when you see her with the exact same odd guy you saw previously. Do you see that person that drives up and just sits in their car for hours? That’s a cop. Normal people get out of their car when they arrive at their destination, and go in a building, but these people have no place outside of their vehicle to go.
And then you have the CIs who do look like normal people but they don’t act normal. If they speak with you, they ask a bunch of intrusive questions. That person over there walking through the area with a camera, taking pictures of nothing in particular; another undercover. That person sitting on a bench that only looks up when you go outside; is part of the same stakeout. That phone call you get, that claims to be a misdial, your power going out, those are signs that you are minutes away from being raided once you confirm active presence.
Getting information on what is going on inside your home is not difficult anymore. If you have a cell phone account, it can be not only monitored for activity but also location. However, the internet is their greatest resource. If they can gain access to your router, they can monitor all of your internet activity. They can monitor you porn activity just to discover what your attractions are and send in an informant. Or they can access any camera and microphone you have connected to the internet and use it for their surveillance purposes.