Does anyone remember what time that Derby party was? I'm wondering if the perps knew about that party, and knew most of the permanent residents there would be attending it. If a majority of the people were at a party, or preparing for the party, they would be distracted and not notice what's going on around them as much as they might if they were just sitting on their porches or docks, and enjoying the day.
"IF" the perps stayed at the home for any significant amount of time, then IMO they knew others were occupied and less likely to come snooping around. OR they were extremely familiar with the property, and their presence there wouldn't set off any alarms to anyone that saw them there. Otherwise, this was a rather brazen crime. Too many chances of someone coming to check on the Dermonds, or pick them up for the Derby party, or stopping by for a chit chat, etc. I just don't see a random stranger spending much time at the residence. IMO, they would come in, commit their murders, and get out.
Too much just doesn't add up. If the purpose was to murder them, then why not just do that, and leave? Why behead Mr. Dermond, and why remove Mrs. Dermond from there? Much easier to just murder and leave. Maybe it gave the perps a bit of time in getting outta the area, or to another state while the LE was searching for Mrs. Dermond, but I just don't see that. IMO, there would have been one group of LE looking into the murder of Mr. Dermond, the crime scene with another group, and the abduction of Mrs. Dermond another group. So I just can't see the purpose other than adding a sense of terror among the residents, family, and LE.
Of course I don't know if Mrs. Dermond was deceased before going on the boat or not. Or even IF she went on a boat, but I cannot see her being gagged, blindfolded, or restrained and walking to the dock. Just don't see that happening. Can you imagine how much time it would take to get an elderly lady down that slope while being restrained??? Nah. And if she walked down to the dock, the dogs should have picked up her scent. Which they might have, we don't know. Maybe that's why Sills is sure a boat was used at some point. But then again, did the Sills ever walk the property? Did they walk to the dock and relax on that couch or whatever it is on the dock? Only those closest to the Dermonds would know. Did the perp take Mrs. Dermond alive with the intent to demand a ransom, and quickly decided that wouldn't work? Who knows at this point.
When this case is solved, I think it's going to be rather straight forth, versus our many theories.
As for Mrs. Dermond floating to where she ended up, looking at the layout of the lake only, IMO, she would have surfaced in one of the coves before coming to where she was "IF" she was placed in the water at their dock. Put in the water in larger open area, she may have floated near the dam. BUT, I do think she was weighted down with something, and the perp didn't feel she would surface. Considering the amount of debris, especially the trees in that lake, it is almost a miracle she did surface! Many bodies are caught in debris and never found. And depending on the type of fish in that lake, it's possible she might not have ever been found. Now WHO would benefit from that??
IMO, the bottom line in solving this case is figuring out WHO benefited from their deaths. WHO felt they were being slighted, or have been done wrong? What was their motive? Nothing stolen that we know of. If they had a safe at home, we don't know about it. If they kept any cash at home, we don't know about it. Was there anyone the Dermonds had been assisting over time. Maybe to help them get on the right path, or given them money in the past to keep them afloat with the declining economy? Did they mentor anyone in becoming successful, and floated them some money to get started, and the money stopped?
Or was this truly some random killer, that killed just to kill? Was the Dermonds the true target, or was their deaths to send a message to someone else to say "see we told you we are serious!"? IMO, almost a month later, and we truly do not know anything about the Dermonds.
When will Sills speak again? We get bits and pieces for a few days, and then nothing for a week, then drips again for a few days, and then silence again. I'm sure there is a purpose for that, and as someone else said, most likely what FBI is saying he should release. Maybe they have suspects in their sights, and are watching reactions to the news that is released.