Albert Barnes Commentary Esther 2:23

"And when inquisition was made of the matter, and it was found to be so, they were both hanged on a tree: and it was written in the book of the chronicles before the king." — Esther 2:23 (ASV)

Both hanged on a tree — i.e., “crucified” or “impaled,” the ordinary punishment of rebels and traitors in Persia.

The book of the chronicles — Ctesias drew his Persian history from them, and they are often glanced at by Herodotus.