| Clue | Source | Date |
|---|---|---|
| Sightings | The Times Concise | 15 Aug 2021 |
| Observations | LA Times Daily | 08 Feb 2020 |
| Observations | The Washington Post | 08 Feb 2020 |
| Furtive observations | USA Today | 01 Mar 2018 |
| Furtive observations | ||
| Spottings or detections | ||
| Sightings | ||
| Sightings | ||
| Furtive observations | ||
| Observations | ||
| Sightings | ||
| Undercover operations | ||
| Undercover operations | ||
| Observations | ||
| Observations | ||
| Sightings | ||
| Secret sightings | ||
| Observations |