It was first seen on reddit back in 2017, on r/The_Donald. A poster brought the tweet to the attention of the users on that sub, and was particularly concerned about the tweet, because at that time (according to the original poster) ISIS had never given any forewarnings of terror attacks before. The person posting the tweet found the tweet alarming.

{edit}. ISIS Described their motive for wanting to target Las Vegas due to it being "sin city," and such, and ISIS also stated that they were going to attack another city too, New York if I recall correctly, but I may be mistaken on which city the second one was.

It was first seen on reddit back in 2017, on r/The_Donald. A poster brought the tweet to the attention of the users on that sub, and was particularly concerned about the tweet, because at that time (according to the original poster) ISIS had never given any forewarnings of terror attacks before. The person posting the tweet found the tweet alarming.