They probably saw it come down.
4 seconds sound clip from the The War of the Worlds (1953) movie soundboard.
You can hear this line at 00:05:46 in the DVD version of the movie.
Quote context
[...]
- We're getting this under control. We won't need any more help. Over.
- Okay. Send the tanker in, but you can stand by until that thing cools off. Over.
- I think somebody ought to check on it. Over.
- Well, there's some fellas fishing at Pine Summit.
- They probably saw it come down.
- Can't get near enough to see it very well. It's too hot.
[...]