One of the most common and devastating forms of lone-actor violence involves driving into crowds. In 2016, Mohamed Lahouaiej-Bouhlel used this method to kill 86 people in Nice. In 2011, Anders Breivik detonated a bomb in central Oslo before carrying out a mass shooting on the island of Utøya, leaving 77 dead. Not all lone-actor attacks are as deadly or indiscriminate as these. Some target specific people, as seen in the assassinations of German politician Walter Lübcke in 2019 and British MP David Amess in 2021.
Lone-actor terrorism – also known as lone-wolf terrorism – poses a unique challenge for European states. Traditional counterterrorism tools designed for organised groups like al-Qaeda, Islamic State, or Eta are far less effective against people acting alone. While lone-actor plots are typically less complex, they can still cause significant harm.