The media and spree killings.
There's now been at least six spree killings in the space of less than a month. For the most part I tend to be sceptical about claims of media influence, especially to the extent to which it might by itself trigger copycat behaviour or violence, but there does seem to be some reasonable evidence, at least where it comes to suicide, that sensationalistic coverage and especially emphasis on methods can lead to an increase in the number of attempts by those who already contemplating doing so or are otherwise depressed.
If there is a link, then it might well be because the media cover spree killings very differently to the way they do "normal" murders. A case in point was the Virginia Tech massacre, where Seung-Hui Cho did the work of the 24-hour news networks for them, sending an entire dossier, better described as a manifesto, to NBC, which they did the equivalent of ejaculating over. In almost no other cases would news networks allow killers to justify their crimes in such a way as Cho did, putting himself up as a secular martyr. The hysteria which followed Columbine, where everything and everyone was blamed other than those who had failed to spot the warning signs, succeeded in making Dylan Klebold and Eric Harris into anti-heroes, as the psychiatrist on Newswipe suggests, name-checked by Cho himself as previous victims whom he aspired to emulate.
There are of course other explanations, often that those behind such sprees have been planning them for some time and that the dates they actually chose to carry out their murders are simply coincidence. Certainly the current economic situation, which will increase the number who undergo utter desperation at their current lot, hardly helps matters. Other cases, such as the Oakland police shootings, just seem to be down to all those involved, including the shooter, being in the wrong place at the wrong time. Even so, that doesn't alter the fact that the media doesn't need to report these killings in the way in which the clip identifies. If there's even the possibility that such sensationalism can contribute to those who subsequently go postal, the media has the best possible reason for scaling back the coverage.