LONDON (AP) — Britain's Home Secretary says the investigation into the nerve agent attack on a Russian ex-spy and his daughter is focusing on three sites — his home, a pub and a restaurant.

Amber Rudd told the BBC on Thursday that enormous resources are being directed at trying to figure out who might be responsible for the poisoning of Sergei Skripal and his daughter, Yulia.

Rudd, who is in charge of public security issues, says the police officer also injured in the incident Sunday is also in serious condition but is conscious and talking.

Rudd declined to say if she believed Russia was behind the attack, but says Britain will "if it is appropriate, attribute it to somebody. If that is the case, then we will have a plan in place."