Recently, I came across a Tweet in which the user made a credible threat of mass homicide and injury using bombs. I was aghast and uncertain how to handle it, but, following the official advice "If you see something, say something", I persevered.
Although I hadn't had occasion to use the feature before, I found that it is easy to access Twitter's tweet-reporting forms by selecting the "Report" option from the drop-down at the upper-right corner of the offending tweet. This took me to a sequence of forms that was rather straight-forward:
So, there you have it. Hopefully, you'll never come across such threats on Twitter, but if you do, remember that if each of us reported apparent perpetrators, they'd soon see the wisdom of ceasing to make such threats and all of us would enjoy a much improved social media experience.
Not to mention reduced risk of being head-sploded.