As a fiction writer, I do research on espionage, sabotage and even methods of assassination all the time. But I'm not going to make a salted bomb and nuke Jerusalem even though that is an entirely viable evil plot that may even create a net negative death toll.

True poisoners, as Agatha Christie notes, use thallium, not arsenic nor cyanide (though ricin is good if you can get it.) Thallium assassins are also self-regulating, like demolitions experts, killing off those insufficiently careful when handling the stuff.

Modern police are lazy until enough of a stink is made to find a culprit for a specific incident, which is why modern assassins targeting VIPs will find a self-radicalized desperado and point them toward the target. This is the sort of thing FBI is looking for in the investigations of Crooks and Routh. They are likely just blue suicides (or green suicides in this case) but finding a operative pointing them towards Trump would indicate an actual plot. But even if those tracks are found, it would unlikely lead to a specific identity.

I know about this not just to write fiction, but also to understand how things happen, how our fall into one party autocracy and societal collapse plays out. And yes, it means I do a lot of web searches that might excite an onlooking behavioral research agent. Sadly, they'd find I'm yet another boring false positive, though if the nation does succumb to autocracy, I'd certainly write for the resistance. FBI may not care so much about that.

We often look up creepy things just so see if we can, and we do that a lot more than because we're eager to build a bomb or fast-track our inheritance.