| Clue | Source | Date |
|---|---|---|
| *Unmanned aerial attack | LA Times Daily | 09 Apr 2019 |
| *Unmanned aerial attack | The Washington Post | 09 Apr 2019 |
| *Unmanned aerial attack | ||
| Unmanned aerial attack | USA Today | 24 Jul 2018 |
| Unmanned aerial assault | USA Today | 16 May 2018 |
| Unmanned aerial assault | ||
| Unmanned aerial attack | ||
| Unmanned aerial attack | The Washington Post | 16 Dec 2016 |