The first public response to the poisoning came on 6 March. It was agreed under the
Counter Terrorism Policing network that the
Counter Terrorism Command based within the
Metropolitan Police would take over the investigation from
Wiltshire Police. Assistant Commissioner Mark Rowley, head of Counter Terrorism Policing, appealed for witnesses to the incident following a
COBR meeting chaired by
Home Secretary Amber Rudd. Samples of the nerve agent used in the attack tested positive at the
Defence Science and Technology Laboratory at
Porton Down for a "very rare" nerve agent, according to the UK Home Secretary. 180 military experts in chemical warfare defence and decontamination, as well as 18 vehicles, were deployed on 9 March to assist the Metropolitan Police to remove vehicles and objects from the scene and look for any further traces of the nerve agent. The personnel were drawn mostly from the Army, including instructors from the
Defence CBRN Centre and the
29 Explosive Ordnance Disposal and Search Group, as well as from the
Royal Marines and
Royal Air Force. The vehicles included
TPz Fuchs operated by Falcon Squadron from the
Royal Tank Regiment. On 11 March, the UK government advised those present at either The Mill pub (now,
The Bishops Mill, 7, The Maltings) or the
Zizzi restaurant in Salisbury on 4 and 5 March to wash or wipe their possessions, emphasising that the risk to the general public was low. Several days later, on 12 March, Prime Minister
Theresa May said the agent had been identified as one of the Novichok family of agents, believed to have been developed in the 1980s by the
Soviet Union. According to the Russian ambassador to the UK,
Alexander Yakovenko, the British authorities identified the agent as
A-234, which is derived from an earlier version known as A-232. By 14 March, the investigation was focused on Skripal's home and car, a restaurant in which they dined, a pub where they had drinks, and a bench, outside The Maltings shopping center in Salisbury, where the two fell unconscious. A recovery vehicle was removed by the military from
Gillingham in Dorset on 14 March, in connection with the poisoning. Subsequently, there was speculation within the British media that the nerve agent had been planted in one of the personal items in Yulia Skripal's suitcase before she left Moscow for London, and in US media that it had been planted in their car.
Ahmet Üzümcü, Director-General of the
Organisation for the Prohibition of Chemical Weapons (OPCW), said on 20 March that it will take "another two to three weeks to finalise the analysis" of samples taken from the poisoning of Skripal. On 22 March, the
Court of Protection gave permission for new blood samples to be obtained from Yulia and Sergei Skripal for use by the OPCW. By 28 March, the police investigation concluded that the Skripals were poisoned at Sergei's home, with the highest concentration being found on the handle of his front door. On 12 April the OPCW confirmed the UK's analysis of the type of nerve agent and reported it was of a "high purity", stating that the "name and structure of the identified toxic chemical are contained in the full classified report of the Secretariat, available to States Parties". A declassified letter from the
UK's national security adviser, Sir
Mark Sedwill, to NATO Secretary General
Jens Stoltenberg, stated Russian military intelligence hacked Yulia Skripal's email account since at least 2013 and tested methods for delivering nerve agents including on door handles. The
Department for Environment confirmed the nerve agent was delivered "in a liquid form". They said eight sites require decontamination, which will take several months to complete and cost millions of pounds. The BBC reported experts said the nerve agent does not evaporate or disappear over time. Intense cleaning with caustic chemicals is required to get rid of it. The Skripals' survival was possibly due to the weather – there had been heavy fog and high humidity, and according to its inventor and other scientists, moisture weakens the potency of this type of toxin. On 22 April 2018, it was reported that British counter-terror police had identified a suspect in the poisoning: a former
Federal Security Service (FSB) officer (reportedly a 54-year-old former FSB captain) who acted under several code names including "Gordon" and "Mihails Savickis". According to detectives, he led a team of six Russian assassins who organised the chemical weapons attack. Sedwill reported on 1 May 2018 however that UK intelligence and police agencies had failed to identify the individual or individuals who carried out the attack. On 3 May 2018, the head of the OPCW,
Ahmet Üzümcü, informed the
New York Times that he had been told that about 50–100 grams of the nerve agent was thought to have been used in the attack, which indicated it was likely created for use as a weapon and was enough to kill a large number of people. The next day however the OPCW made a correcting statement that the "quantity should probably be characterised in milligrams", though "the OPCW would not be able to estimate or determine the amount of the nerve agent that was used". On 19 July the
Press Association reported that police believed they had identified "several Russians" as the suspected perpetrators of the attack. They had been identified through
CCTV, cross-checked with
border entry data. On 6 August 2018, it was reported that the British government was "poised to submit an extradition request to Moscow for two Russians suspected of carrying out the Salisbury nerve agent attack". The Metropolitan Police used two
super recognisers to identify the suspects after trawling through up to 5,000 hours of CCTV footage from Salisbury and numerous airports across the country. British Prime Minister Theresa May announced in the
Commons the same day that British intelligence services had identified the two suspects as officers in the
G. U. Intelligence Service (formerly known as GRU) and the assassination attempt was not a rogue operation and was "almost certainly" approved at a senior level of the Russian government. May also said Britain would push for the EU to agree new sanctions against Russia. On 5 September 2018, the Russian news site Fontanka reported that the numbers on leaked passport files for Petrov and Boshirov are only three digits apart, and fall in a range that includes the passport files for a Russian military official expelled from Poland for spying. It is not known how the passport files were obtained, but Andrew Roth, the Moscow correspondent for
The Guardian, commented that "If the reporting is confirmed, it would be a major blunder by the intelligence agency, allowing any country to check passport data for Russians requesting visas or entering the country against a list of nearly 40 passport files of suspected GRU officers." On 14 September 2018, the online platforms
Bellingcat and
The Insider Russia observed that in Petrov's leaked passport files, there is no record of a residential address or any identification papers prior to 2009, suggesting that the name is an alias created that year; the analysis also noted that Petrov's dossier is stamped "Do not provide any information" and has the handwritten annotation "S.S.," a common abbreviation in Russian for "top secret". On 15 September 2018, the Russian opposition newspaper
Novaya Gazeta reported finding in Petrov's passport files a cryptic number that seems to be a
telephone number associated with the
Russian Defence Ministry, most likely the Military Intelligence Directorate. As part of the announcement Scotland Yard and the
Counter Terrorism Command released a detailed track of the individuals' 48 hours in the UK. This covered their arrival from Moscow at
Gatwick Airport, a trip to Salisbury by train the day before the attack, stated by police to be for
reconnaissance, a trip to Salisbury by train on the day of the attack, and return to Moscow via
Heathrow Airport. On 26 September 2018, the real identity of the suspect named by police as Ruslan Boshirov was revealed as
Colonel Anatoliy Vladimirovich Chepiga by
The Daily Telegraph, citing reporting by itself and Bellingcat, with Petrov having a more junior rank in the GRU. The 39-year-old was made a
Hero of the Russian Federation by decree of the President in 2014. Two European security sources confirmed that the details were accurate. The BBC commented: "The BBC understands there is no dispute over the identification." However, that statement was subsequently deleted from Twitter. On 8 October 2018, the real identity of the suspect named by police as Alexander Petrov was revealed as
Alexander Mishkin. On 22 November 2018, more CCTV footage, with the two suspects walking in Salisbury, was published by the police. On 19 December 2018, Mishkin (a.k.a. Petrov) and Chepiga (a.k.a. Boshirov) were added to the sanctions list of the
United States Treasury Department, along with other 13 members of the GRU agency. On 6 January 2019, the
Telegraph reported that the British authorities had established all the essential details of the assassination attempt, including the chain of command that leads up to
Vladimir Putin. In February, a third GRU officer present in the UK at the time,
Denis Sergeev, was identified. In September 2021, the BBC reported that
Crown Prosecution Service had authorised charges against the three men but that formal charges could not be laid unless the men were arrested. ==Response of the United Kingdom==