Enemas and lubricant have batch numbers, so LE could probably track the distribution and locate where they were purchased. LE would also have video of exactly how the POI entered the room and who may have been there before. The only person reported to have been questioned is a woman. So I'm thinking it may well have been a women there with David before 7:34 pm text home. Depending on how long it would have taken him to get home, or if he really had any intention to get home, at this point, the text could have either been cover or a signal, depending on who is involved, or just a text before he hit the shower, to make his way home.
David Messerschmitt, was a smart guy, seems much loved, befriended, and honored in loss. I think he thought he was safe when he checked into the hotel to meet somebody, if that is what he did at all. He may have not been so discrete that he couldn't be traced in hours, so not so concerned about discovery. Indeed, if he did send the text, then until that time, he may have had nothing to fear, feel no danger, it seems to me.