I believe the Spierers know who is on that video. I believe the Spierers know all of the men involved in taking her somewhere (cell phone records, car searches, cadaver hits) but know that without a body, they may never get a conviction. I honestly believe the Spierers know who killed their daughter and are appealing to others who may have been witnesses to come forward and tell the truth, even anonymously, just to be able to bring their daughter home. I believe that LE has a mountain of evidence that we are not privy to and have listed these POIs in order of culpability, #1 being the killer, perhaps #2 disposing of the body, providing the drugs, etc. LE does not leave the family out of anything. They are informed of everything. But like LE, they have to be tight lipped as well to avoid botching a conviction. They're putting pressure on a POI or few and appealing to their conscience. This makes me think they know this person by the tone of their messages and tweets. Perhaps they know he didn't kill her per se, but was involved in hiding her body. That's the message I get from the Spierers. They aren't speaking to some Joe off the street so to speak. I believe this is someone they know and know well.