IMO, LE do not usually just casually throw out the possibility of linkage to other missing persons cases/murders so the fact that they did this is significant. I think they strongly suspect this was either not his first murder or at least, not the first serious assault. IMO the search for other potential victims should not be narrowed to just women similar to Erica. News articles have described him as a transient truck driver. One has to wonder if COVID has altered his usual work schedule or impacted his access to potential victims. Erica may be the first that he killed after using a dating app to meet. He may have other victims with totally different ways that he selected/came across them (they could be women working at truck stops, etc).