Police say the stabbing of a long-serving member of Parliament during a meeting with constituents was a terrorist incident, and that they believe the attacker acted alone.

The Metropolitan Police said in a statement released early Saturday that the early investigation into the slaying of Conservative lawmaker David Amess “has revealed a potential motivation linked to Islamist extremism.”

Amess, 69, was attacked around midday Friday at a Methodist church in Leigh-on-Sea, a town about 40 miles (62 kilometers) east of London. Paramedics tried without success to save him. Police arrested the suspect and recovered a knife.

A 25-year-old man was arrested at the scene.

Police said that counterterrorism officers were leading the investigation into the slaying.

They did not identify the suspect, who was held on suspicion of murder.