What is a word that means "omen" but for something that has already happened? [closed]

Just as the subject says, I'm looking for a noun that is similar in meaning to "omen," but that refers not to something that will happen, but rather to something that has already happened.

Is there something more precise than "sign?"

"Lemminkäinen’s mother receives a ___ that her son has been killed, and journeys to the underworld to resurrect him."

Note that the mother is far away from the place of her son's death, and only learns of it through a sign, or a "reverse omen," if you will.

Solution 1:

Based on the sentence you provided:

Vision

an experience of seeing someone or something in a dream or trance, or as a supernatural apparition.

Postmonition (formed by post- "after in time" and monition meaning "warning" as opposed to a premonition - future) - not a dictonary word.

dreaming something happened, after it happened, without knowing it happened.

Solution 2:

I would recommend the word "Revelation".