UNLV shooter Anthony Polito sent 22 letters to universities across the U.S., including at least one with a white powder substance. A "last will and testament" was also found in his apartment.

Billionaire Elon Musk's decision to rebrand Twitter as X could be complicated legally: companies including Meta and Microsoft already have intellectual property rights to the same letter.

From PayPal, to Twitter and even one of his children, the tech entrepreneur has a long affiliation with the letter X. Here's what we know about it.