As reported by Censor.NET citing a statement on the attempted murders of Sergei Skripal and his daughter Yulia in Salisbury issued by Scotland Yard March 19, the investigation is highly like to take many months since this is one of the largest and most complex investigations undertaken by British counter terrorism policing.
"Searches are ongoing in the Salisbury area and at this stage it is not possible to put a timescale on how long these may take to conclude. Specialist search officers wearing protective equipment continue to carry out a meticulous, systematic search for evidence to support the investigation.
"That search is being carried out based on expert scientific advice to assist detectives in understanding the specific locations that are of most relevance to their lines of enquiry.
"Areas searched to date include large open spaces, commercial and residential properties and vehicles.
"The full range of relevant tests are being carried out and, as reported, this includes support from international partners.
"This is an extremely challenging investigation and police and partners continue to manage a number of unique and difficult issues.
"Around 250 counter terrorism detectives continue to work round the clock, supported by a full range of experts and partners.
"The response from the public has been of huge use to the investigation in terms of witness statements and material provided to the investigation website.
"Officers continue to trawl through 4,000 hours of CCTV and examine nearly 800 exhibits that have been seized. Around 400 witness statements have been taken and many more will follow in the coming days and weeks.
"Despite the complexity of this investigation and the unique challenges, as with all investigations, police have a duty to balance the release of information into the public domain as part of that process with protecting the integrity of our work and planning for any potential legal proceedings," the police said in a statement.
As reported, Russian ex-spy Sergei Skripal, 66, and daughter Yulia Skripal, 33, remain critically ill in hospital, after they were found unconscious on a bench in the Wiltshire city on March 4. The UK government says they were poisoned with a nerve agent of a type developed by Russia called Novichok and PM Theresa May said she believed Moscow was "culpable."
May has said the UK will expel 23 Russian diplomats as part of a "full and robust" response – prompting Russia's Foreign Minister Sergei Lavrov to say it will "certainly" expel British diplomats in response.
On March 16, NATO Secretary General Jens Stoltenberg said the alliance had "no reason to doubt the findings and assessments by the British government" which suggested Russian responsibility. He said the "UK is not alone" and NATO allies gave "strong political support" to Britain, following a joint statement from the U.S., France and Germany backing May's government and a pledge of support from Australia.