The text known as Book of the Apocalypse of Baruch aka 2 Baruch (late 1st or early 2nd century AD) states the following in chap 56:
[Adam] became a danger to his own soul: even to the angels. For, moreover, at that time when he was created, they enjoyed liberty. And became he a danger some of them descended, and mingled with the women. And then those who did so were tormented in chains. But the rest of the multitude of the angels, of which there is (no) number, restrained themselves.
And those who dwelt on the earth perished together (with them) through the waters of the deluge. These are the black first waters.
Just as an FYI: the reference to black water pertains to the text’s so called “Messiah Apocalypse” which contains “The Vision of the Cloud with black and white Waters” which begins with “…when I had said these things I fell asleep there, and I saw a vision, and lo! a cloud was ascending from a very great sea, and I kept gazing upon it) and lo! it was full of waters white and black, and there were many colors in those self-same waters, and as it were the likeness of great lightning was seen at its summit.”
This text is, of course, referencing the Genesis 6 affair and also 2 Peter 2:4 which states that “God spared not the angels that sinned, but cast them down to hell, and delivered them into chains of darkness, to be reserved unto judgment.”