Does anyone have any thoughts on the dark marks visible to the left of the cistern hatch in this photo?
Note that the marks are absent in this later photo:
There could be an innocuous explanation for those marks. Perhaps they were created on the day of the body's discovery; they look greasy, so perhaps the maintenance man (or subsequent investigators) dirtied it by resting tools or their own appendages on it.
But what if the marks were already there before the gruesome discovery was made? Possible evidence of a struggle (or more sinister labours), left unwittingly at the scene (or even unknowingly, if it was too dark to see the marks)?
If they were left by a perpetrator, they could yield valuable information. But that's a big "if". This is all speculation, of course, but the presence of those marks -- and their absence in later photos -- is truly food for thought. Thoughts, anyone?
Edit: Perhaps the marks were left by someone completely uninvolved with the case, but I'm inclined to doubt it. Why only that cistern (as far as I can tell), and why only near the hatch?