I am totally unfamiliar with FOXTROT but typically apps that launch themselves as you describe, do so through either a LaunchAgent or LaunchDaemon. Launch Daemons can be found in /Library/LaunchDaemons and Launch Agents in ~/Library/LaunchAgents or less often in /Library/LaunchAgents.
NOTE: /Library is on the boot drive root and ~/Library is found in your user home folder.
LaunchAgents & Daemons files are often protected by the system and can be difficult to delete — they just keep coming back. Start with a
- On your Mac, choose Apple menu > Shut Down.
- After your Mac shuts down, wait 10 seconds, then press the power button.
- Immediately after your Mac starts (some Mac computers play a startup sound), press and hold the Shift key.
- Release the Shift key when you see the gray Apple logo and progress indicator.
Then delete the LaunchAgent/LaunchDaemon and empty the trash. Finally Reboot normally and hopefully that will solve your problem.
By-the-way I found several apps with the sobriquet FOXTROT. Out of curiosity which one do your have and what does it do?
edited to clarify title...