I've added your suggested indicators in bold and my comments in regular type. My comments are not necessarily case-specific. They are mostly generic, with some case-specific reflections.
Carana raises an excellent point on another thread and rightly asks what evidence would one reasonably expect to find in an abduction?
Evidence of an abduction can include the following:
* A missing person.
Yes, but this might be classified as an indicator as opposed to evidence. It doesn't exclude other possibilities.
* Stolen property.
Not sure about that one. People are sometimes briefly abducted or simply mugged in order to steal jewellery, an expensive phone or what not... but would one expect property to be missing if an abduction is the primary objective?
* A break-in or forced entry.
Possibly, although that wouldn't exclude entering via the unlocked door or the use of a duplicate key.
* Unusual footprints including soiling on sills/floors/carpets.
There were footprints, but they were unuseable, in part to due to contamination by fingerprint powder. The search for fingerprints was limited.
* Persons acting suspiciously nearby.
There were, whether they are relevant or not remains to be seen.
* A ransom demand.
In a kidnapping.
* Sightings of the missing person. Tannerman (seemingly now excluded) and Smithman who doesn't appear to have been identified yet. It's not clear if the couple with a child near the Lagos marina / station was ever identified.
Despite the publicity, her appearance could have been changed and with time she wouldn't resemble the little girl in the photos we all remember. The fleck in her eye wouldn't stand out at a distance and sunglasses or slightly tinted glasses would cover that up in public.
Even though there were numerous presumably false "sightings", once the leaks of suspicions about the parents, and then Amaral's book insisting that she was dead and that the parents were involved, how many people seriously continued to remain vigilant?
Please feel free to add to the list and discuss.
Adding a few of my own to the list.
* Unexplained fibres or hairs.
There are hairs that have still not been identified. A sweep for hairs / fibres doesn't appear to have taken place throughout the flat. She could have been taken while in the bathroom or in her parents' bedroom, for example.
* Unexplained disturbance of objects.
The only thing that seems unexplained is the door apparently being found further open than usual, although a breeze when one or other people walked in / out or a child walking out could possibly explain that.
* Abandoned belongings of the person.
Clothes, bag, phone, jewellery, bike (for an adult or older child). Only pyjamas would apply in this case and none seem to have been recovered. However, the search of bins took place quite some time after with only a couple of municipal employees to attempt to cover the totality in a very short space of time. If the PJs had been made difficult to recognise, e.g. by burning or shredding, and mixed in with household rubbish, it seems unlikely that they would have been found. The search was, by all accounts, not a fingertip forensic search. PJs could also be weighted down and thrown down a well or in the sea or dumped elsewhere anyway.
* CCTV.
This can often shed light in areas that have CCTV coverage and presumed trajectories / timings / suspected vehicles / unexplained presence in certain areas can be checked. CCTV isn't common in PT, let alone in sleepy villages. The PJ didn't seem to have checked existing security cameras thoroughly as a priority. The only one that might have shown something significant in the vicinity got wiped. The one checked in a nearby petrol station wasn't her. The one at the Paraiso café established the presence of the majority of the group at the time they'd stated, but nothing of direct significance.
A few others could be indicators:
* Unusual phone activity. This was partly checked at the time, but is now being investigated more thoroughly.
* Unfamiliar cars appearing to prowl or suddenly screech off.
No sudden screeching appears to have been noted. "Prowling" is subjective and could simply mean someone innocently searching for a parking spot.
* Family / professional situation.
No known history of familial abuse, complex family situations, desperate financial situations, mental illness, unwanted babies, known enemies in search of revenge, kidnapping for political or financial purposes, etc.
* Indicators related to previous crimes in the area.
- Numerous burglaries or attempted ones had taken place.
- Several assaults or attempted ones on other children had taken place in the area, some of which involved entry to the living space of the families involved, even when parents were there.
- The lack of resources to overhaul the judicial system, a potential lack of coordination between police forces and the absence of a sexual offenders and DNA database may mean that suspects are still out there, moving within PT or even in other European states, or could even be in jail for unrelated offences.
ETA:
* Cigarette butts on a balcony that could have been a potential vantage point. These don't appear to have been collected.
