The domain was registered yesterday[0]. It seems unlikely to have been done so by the alleged shooter.

0 - https://www.whois.com/whois/pepmangione.com

Thanks for sharing. How does we determine if this is authentic? Was this published via a dead man switch?

Also how does this website relate to the Substack that he had, which apparently got censored and blocked by Substack yesterday?

I believe this is the one the media outlets are saying is a fake. Doesn't match the length of the one described by law enforcement and doesn't contain phrases quoted by major media outlets.

This one has been confirmed by some major media outlets as being genuine and matches the description by law enforcement and the select quotes published by established media:

https://www.kenklippenstein.com/p/luigis-manifesto

There could of course be other writings by the suspect, and this could be one, but it's definitely not confirmed.

Seems suspicious. If you look at Archive.org, the site was only crawled on December 9, 2024, and not before.

That also matches the issuance date of the TLS cert and the reported domain registration time with namecheap.

Seeing that too. Will change the title to: "United Healthcare Shooter Unconfirmed Manifesto"

Yes, I did a search and could not independently confirm. Interesting read, but no idea if it’s real.