Like all the best murder mysteries, the killer strikes at the dead of night to ensure he is neither seen nor heard as he administers poison to his unsuspecting victims.

Each bears the same tell-tale scars from the brutal attack - puncture holes where the chemical has been carefully injected.

By the time the drug has taken effect the assassin has vanished leaving the police clueless. More importantly, they are baffled about the motives because the victims have all been historic towering and protected trees in a private Norfolk woodland.

In total, eight trees in Gorleston-on-Sea have been targeted by the culprit who drills holes in either the roots, trunk or boughs before a mystery chemical is poured in and the scar covered up.

So far, one holly tree has died, but seven beech, horse chestnut, holm oaks and poplar trees with preservation orders on them have been diagnosed as “distressed” having lost most of their leaves that created once vast canopies. The oldest is nearly 200 years old.