The shocking act of vandalism that brought down the famous Sycamore Gap tree in northern England also damaged Hadrian's Wall, which once marked the ancient frontier of the Roman Empire.
Archaeological analysis of the damage confirmed "there are some cracks and fragments broken off from two of the facing stones" on the wall, according to Historic England, a government-backed organization that preserves the country's heritage.
Historic England said it will work with the National Trust in forming a plan to repair the damage. It also passed along its findings about damage to the wall, a UNESCO World Heritage Site, to Northumbria Police, which has been investigating what it has deemed "a deliberate act of vandalism."
Since the historic and photogenic tree was cut down in late September, police have now made at least four arrests linked to the case.
The first was the arrest of a 16-year-old boy, who was taken into custody soon after the tree was felled. A man in his 60s was later arrested; officers were seen carrying a large chainsaw away from the home of the man, who is reportedly a former lumberjack.
Last week, Northumbria Police announced two more arrests, of men in their 30s. It did not specify how they might have been connected to the crime.
"I hope this recent wave of arrests demonstrates just how much work has been undertaken by our dedicated specialist teams in what has, so far, been a very difficult and complex investigation," said Detective Chief Inspector Rebecca Fenney-Menzies of the Northumbria Police.
Noting the public anguish over the loss of the tree, Fenney-Menzies said the investigation is continuing.
The Sycamore Gap tree grew in a gully along Hadrian's Wall, thriving in a landscape of rocks and grass. It became a well-loved icon, featured on postcards and even in Kevin Costner's 1991 film, Robin Hood: Prince Of Thieves.
"We believe the tree to be around 200 years old," Jeannette Heard of the National Trust told NPR after the sycamore was cut down. She added, "We are going to protect the remaining tree stump to see if it may grow again so that at least the legacy from the original tree endures."
