The police doing additional investigations, along with a judicial review is normal when anyone disappears. Nothing can be ruled out until the person, or a body is found, regardless of what is considered the most likely explanation. So the various scenarios will always be in peoples minds. Very tough on the partners and family who have to live with not knowing, and people's speculations.
The question marks will always remain until the unknown becomes the known as in the exceptional case of Ian Stewart, in the UK whose first wife's death had for some years been considered a health issue until his conviction for the gruesome murder of his subsequent partner, initially a missing person. There will be other examples to be found on this site.
Helen Bailey murder: Fiance Ian Stewart guilty of killing author as police re-examine death of first wife
Trial date set as Ian Stewart pleads not guilty to murder of wife Diane
Meanwhile the innocent families in these cases have to live in doubt, and some under suspicion. Often following gruelling police attention and with their lives picked to pieces, and then left on hold for various amounts of time. The emotional impact must be huge, with some people withdrawing and others becoming active as DC did initially, and as we saw in the Susan McClean case on here.