- young Muslim male
- travels extensively to / lived in a Muslim country
- linked to another "person of interes"
- has immediate family that currently lives in a Muslim country
- sends money to family members in a Muslim country
- he returned alone to the US while the rest of his family stayed in Egypt.
Now, although traking does seem like an over reaction in this case you gotta ask yourself what job it is the FBI is tasked with. I have yet to see a comment mentioning the end of the article where the FBI agent says to the kid "don't worry you're boring", meaning they figured out he is not a threat. Also, we do not know why the FBI specifically wanted to track this kid. Perhaps the kid knows people even more interesting and they want to use him to get to them. Who knows.
I also do not agree with warrantless tracking and if they did need to get a warrant perhaps they would have thought more and decided not to track this kid. That said, the FBI watches potential threats all the time and this kid has all the flags, for better or worse.