Hi,
@TIGER0822. I think a lot of folks here on WS have been speculating as to why LE seemed to narrow their focus very early on in this case. First, to clarify a couple of things: LE has never admitted that they found SM’s bike on the night she was reported missing. That information came from BM’s nephew, TN. I believe the personal item you are referring to was actually found on the following Thursday, 10/15. That find, which LE did admit to, was discovered up near the intersection of Hwy 50 and Rte 225 and caused a large search to be initiated on the following day, Friday. That search resulted in Hwy 50 west towards Monarch Pass being closed off for a greater part of the day on Friday. To our knowledge no additional evidence was found during that search.
Going back to your original question, no one but LE knows at this point what compelled them to narrow the focus of their search so early. They were very quick to rule out accident and mountain lion attack. It seems they have also found no evidence of an abduction. The most common theories that we have come up with is that something about the bike itself was off early on. Perhaps it was un-rideable, perhaps it was staged at its location. Perhaps a neighbor reported something, a neighborhood video caught something on camera, or there was something very incriminating at the scene.
You are correct when you say you might expect LE to be reassuring and comforting to the family of a missing person and that they would stand with them to get find out what had happened to their loved one. BM has been vocal, (on the TD video), about his criticism on how LE handled this case from the beginning, but that may be a boisterous bluff. We don’t know what LE found out very quickly but it appears to have been quite incriminating.