LONDON (AP) — Authorities have broadened their investigation into the nerve agent poisoning of an English couple, seizing a car in a third community in southwestern England.

Police seized a car in the large town of Swindon as part of their probe into the death of 44-year-old Dawn Sturgess, who was exposed to Novichok, a military-grade nerve agent produced in the Soviet Union during the Cold War. Her partner Charlie Rowley, 45, is critically ill.

Police have said the working theory is that their exposure was linked to the earlier Novichok attack in March on ex-Russian spy Sergei Skripal and his daughter Yulia in the city of Salisbury.

Wiltshire Police tweeted Monday that the car was being "safely" removed and reminded the public that the risk of contamination with the agent was low.