This is the 3087th most frequent Russian word.
исчезли
"Исчезли" means "disappeared."
Here, 'исчезли' is used to mean something went out of sight.
Лучи солнца исчезли за горизонтом.
The sunrays disappeared behind the horizon.
In this sentence, 'исчезли' suggests that the traces became undetectable.
Все следы преступника исчезли.
All traces of the criminal disappeared.
Here, 'исчезли' indicates that the doubts ceased to exist.