>>359367
I'm sure that somebody in one of the bloodline families in NY who have big interests in pharma, went a bit roque, got some cornstarch and a bit of black pepper and sent a letter. Unfortunately these people are stupid. Envelopes, even modern machine made ones, are not airtight and therefore not powderproof. The mail came in, a secret service employee started to open it, powder was detected and a well rehearsed plan went into play.
As you say the story about the Trump family member was for optics. And no doubt, after their portable lab tested and identified the substance, one of the family asked to allow someone to touch the powder so that the story of getting it one hands could be truthfully told.
Postal mail in a city like NY is rather easy to trace and no doubt the fool used letterhead or a company postage meter to make the tracing job that much easier.