What were the numerous other factors that were considered in the beginning?
The main thing in my mind would be different witness accounts (for instance, we know a sketch was made just a couple of days after the crime that was not used until 2019).
The other two things that associate in my mind with the beginnings of investigations would be two of the first things investigators do: complete a victimology on the person who was murdered and complete a canvass of people who may have seen or heard something that pertains to the crime.
So two other possible factors would be anything that came to light in the victimology assessment or anything that came to light in the statements of those canvassed (could be searchers, could be neighbors, could be other people walking the trails, etc).
Another factor that LE could have had early on would be any kind of initial tip. Did it originally check out, but then with the rest of the information gathered since 2019, does it seem like it might mean something different?
And the other factor would be anything that was believed about the crime scene evidence itself early on, that changed in the course of the investigation. Sometimes as time passes there are different interpretations, as different technology or a different specialist's knowledge is brought to bear.