LONDON—British government security ministers held an emergency meeting Saturday to discuss the poisoning of a Russian who spied for Britain as police backed by soldiers continued to search the town where he was attacked with a nerve agent.

The meeting led by Home Secretary Amber Rudd is similar to the ones convened after extremist attacks and other threats to national security. It will cover the latest police and intelligence reports from Salisbury, where a military-supported investigation has turned to the cemetery where the ex-spy’s wife and son are buried.

Police are looking for clues to what sickened Sergei Skripal, 66, a former Russian military intelligence officer who was convicted of spying for Britain, and his daughter, Yulia, 33. They remain in critical condition, poisoned with what authorities said was a rare nerve agent.

The father and daughter were found unconscious on a bench near the River Avon in Salisbury on March 4. A local restaurant and pub have been searched and remain closed to the public. Police also are collecting evidence from Skripal’s house, as well as at the gravesites of his son and wife.

Skripal was convicted in 2006 of spying for Britain and released in 2010 as part of a spy swap. The former intelligence agent lived out of the public eye in Salisbury, 90 miles (140 kilometers) southwest of London.

A friend of his daughter’s, Irina Petrova, told The Associated Press that Yulia Skripal enjoyed England but preferred living in Moscow, where she made her primary home.

“She’s not a typical Russian,” Petrova said. “She was so easygoing. Even when something happened to her dad, she never spoke of any problems. And neither did her mother. They were so alike. Never did they speak of problems. Even in difficult times, they always had smiles and pleasant faces, not grumpy.”

Petrova described Sergei Skripal as “a good, kind man” and said it was terrible that the “whole family disappeared in basically one instant.”

Police have not released details about the specific nerve agent used in the attack. One theory is that the Skripals were poisoned in his house before visiting a restaurant and a pub and becoming ill.

British officials say there is not a public health threat but some residents have become alarmed by the site of investigators wearing extensive hazardous material protection gear.

About 180 marines, soldiers and air force personnel with expertise in chemical weapons, decontamination and logistics have been called in to help with the probe and to remove vehicles that may have become contaminated.

Your support matters…

Independent journalism is under threat and overshadowed by heavily funded mainstream media.

You can help level the playing field. Become a member.

Your tax-deductible contribution keeps us digging beneath the headlines to give you thought-provoking, investigative reporting and analysis that unearths what's really happening- without compromise.

Give today to support our courageous, independent journalists.