Hakatan:
Links are generally not allowed, but according to https://www.theyeshivaworld.com/coffeeroom/topic/moderation-memos-posting-tips-and-important-links it’s OK to link to YWN and Hebrew Books.
So, here is a link to a source https://www.hebrewbooks.org/pdfpager.aspx?req=41925&pgnum=194
There is no known contemporary record, but the story seems to have been passed down as a mesorah through the families of a few people who were there.
I’ve heard the story from my own rebbeim who heard from their rebbeim long before R’ Dov Eliach published it in Avi Hayeshivos.
So all I’m saying is that there seems to be a solid mesorah for the story.