In Miriam Carey's case, it was members of her own family.
I think this author should get fitted for a tin foil hat. We joke about NSA surveillance here on FR, but I don't think anyone is planning to commit a violent act over it.
The revelations about NSA surveillance have been in the news for a couple of months, and more is probably forthcoming. If someone is already teetering on the edge of sanity, these bits of news may be the trigger that is pushing them over.
But, I don't think that's a "coincidence". It's simply irrational behavior, and there's no point in trying to attribute it to a rational cause. It's not much different than when we get a cluster of mass shootings. One person does it, and the media coverage appears to trigger others that are already struggling with sanity.
That's not very specific.
Who were these "family members" and who was the first "journalist" they contacted?