Sergei Skirpal

Citing a source close to the investigation, the Press Association reports that police used closed-circuit television to identify multiple Russians who participated in the attack.

Doctors and nurses took steps quickly that saved the lives of Sergei Skripal, 66, and his 33-year-old daughter, Yulia after they were attacked with a deadly nerve agent on March 4.

In her first appearance on camera since the March poisoning, Skripal said that she was concentrating on nursing her father back to health, but that she eventually hoped to return to Russia.

Secretary-General Jens Stoltenberg, speaking at a news conference in Brussels, said the alliance was withdrawing the accreditation of seven staffers of the Russian mission.

The policeman who responded to the scene of the nerve agent attack on a former spy was released Thursday, as another officer exposed to the deadly chemical was being treated for minor symptoms.