Detectives are continuing to investigate after two people were exposed to the nerve agent Novichok in Amesbury, Wiltshire.
This is a fast-moving investigation involving around 100 detectives from the Counter Terrorism Network who are working around the clock alongside colleagues from Wiltshire police. The focus of the investigation remains identifying the source of the contamination as quickly as possible.
The 45-year-old man and 44-year-old woman, who are both British nationals and from the local area, remain critically ill in hospital today (Thursday, 5 July).
At approximately 10:15hrs on Saturday, 30 June, the South West Ambulance Service was called to a residential address in Amesbury, where the woman had collapsed. She was subsequently taken hospital.
At around 15:30hrs on the same day, the ambulance service was called back to the same address after the 45-year-old man had fallen ill. He was also taken to hospital and Wiltshire police informed.
The Defence Science and Technology Laboratory at Porton Down confirmed to police on Wednesday, 4 July that the man and woman had been exposed to Novichok.
At this stage, no-one else has presented with the same symptoms linked to this incident.
Following further tests of samples from the patients, we now know that they were exposed to the nerve agent after handling a contaminated item.
Detectives are working as quickly and as diligently as possible to identify the source of the contamination.
Meticulous and systematic searches are under way at a number of sites. The safety of the public and our officers remains paramount and the searches will take longer because of the precautions that we must take to ensure there is no outstanding risk.
Officers are wearing protective equipment as they carry out their activity and protective barriers may also be installed at some of these sites.
Cordons remain in place at a number of sites in the Amesbury and Salisbury areas that we believe they visited before they fell ill. This is a precautionary measure while we continue to investigate how they came into contact with the substance.
John Baker House in Salisbury is one of the sites identified and the relevant area within the building was cordoned off. We have today, Thursday 5 July, evacuated the rest of the building in preparation for officers to begin their work there.
There is no evidence that they visited any of the sites that were decontaminated following the attempted murders of Sergei and Yulia Skripal in March this year. We are not in a position to say whether the nerve agent was from the same batch that the Skripals were exposed to.
The investigation into the attempted murders of the Skripals is ongoing as detectives continue to assess all the evidence available.
The possibility that the two investigations might be linked is clearly a key line of inquiry for police. However, Assistant Commissioner Neil Basu stressed on Wednesday, 4 July, the importance of the investigation being led by the evidence available and the facts alone.
We would like to thank the people of Salisbury for their continued support and understanding and renew our appeal for anyone who may have information that could assist with this investigation to contact police on 0800 789 321.
Anyone with health concerns should follow the advice provided by Public Health England or call the dedicated helpline on 0800 092 0410 or 020 7158 0124.