a) If a bad actor had carried a bag of Ricin or Anthrax into the White House in the exact same way someone carried the cocaine in, how long would it take White House security, the Secret Service and the DC police to learn his identity and make the arrest?
b) If your security can make this identification and arrest, why can't you find out who brought in the cocaine?
c) If your security arrangements are unable to quickly learn the identity of the Anthrax terrorist in this scenario, why do any of you have jobs?
This "we may never know" thing is total bullsheite. If Eric Trump had brought in the cocaine, we would have been seeing his ginger face on national news within the first twenty minutes of this story.
They know.