Regarding the hostel... I personally don’t find any behaviour suspicious.
I’ve stayed and worked at a few hostels. Backpackers prefer dorms. It’s the point of staying at a hostel, otherwise they’d book a hotel, air bnb or tent site. In fact, it’s extremely rare for a young, single male backpacker to book a private room. They usually prefer to spend the cash on experiences or gifts for loved ones, because to foreigners, it’s an outlandish fortune to spend on a bed for a night. Theo may have stayed in a private room, but that in itself would be against the norm.
Also know that hostel guests consistently fail to check out properly or on time, and it is never cause for alarm. It wouldn’t be out of the ordinary for the hostel to assume Theo left for good but didn’t check out properly, and didn’t even realise his stuff was still in the room.
In dorms, it’s not immediately apparent who’s bags belongs to whom. On any given day, there are a bunch of bags thrown across the floor and in lockers that housekeeping, rightfully, don’t know or care to which guest they belong to.
The only way they would have noticed, is if the entire dorm checked out one morning yet someone’s belongings remained.
Even then, guests do accidentally leave bags behind and call to claim them when the can. On the odd occasion, a guest will leave belongings behind that later becomes evident they intended to leave behind, things they no longer need.
Even if a bag is left behind, it’s against policy for hostel staff to go through it. In my experience, bags with no evident owners are usually put in a safe place by the manager. Only if it is still there days later, might it be briefly opened (but not rummaged through in detail) to check for identification and a contact number. If still there, police are called in.
Given Theo was supposed to check out on 3 June and already reported missing by family on 6 June, there was no time for hostel staff to become concerned.
A guest disappearing off the face of the earth is practically non-existent. It’s not like there was a precedent for it.
I don’t at all blame the hostel for not immediately realising something was wrong with Theo.
I am also not immediately suspicious of other backpackers staying at the same hostel as Theo. Hostel staff can often tell when a guest isn’t ‘quite right’, out of place or likely to cause trouble.
If there were any obvious characters staying in the hostel at that time, staff would likely have mentioned it to police and they would have been investigated or brought to light as persons of interest who might be able to assist investigation.
It doesn’t rule out theory of involvement of other guests, but to me it is less likely than say… patrons of CMs.
