Possible Clues:

• Couple of views in The Observer?
• One who saw European tree — it's next to a loch
• Onlooker
• *Trial figure who can give a firsthand account
• One report heard in court from Observer
• *True crime watcher
• One who sees firsthand
• Note tree — it is above loch — he saw it
• He observed wood bound by rope lifted over head
• Whodunit interrogatee