Military chemical warfare personnel are among the nearly 200 troops sent to Salisbury to help with the investigation into the poisoning of former Russian spy Sergei Skripal and his daughter.
The operation on Saturday focused on the cemetery where Mr Skripal's wife and son are buried.
Last week would have been Mr Skripal's son's birthday, so it's likely Mr Skripal and his daughter, Yulia, visited, perhaps leaving flowers or other objects. The cemetery was likely visited by Mr Skripal and his daughter before they were poisoned by a nerve toxin.
For experts in chemical, biological and nuclear warfare, even seemingly simple tasks are complex and dangerous. At the cemetery, forensic tents were placed over the graves of Mr Skripal's wife and son.
Around 180 military personnel have been drafted into Salisbury, removing objects and vehicles, including ambulances that may have been contaminated.
Russian Foreign Minister Sergei Lavrov gave his high-level assessment saying, "This is not serious; this is pure propaganda and the whipping-up of hysteria".
But it was a different take from the British Home Secretary who visited the scene.
The operation on the street where Mr Skripal lived has ramped up considerably. The suggestion is now Mr Skripal and his daughter were poisoned at home.
Nick Bailey was one of the first officers to come to the house after their collapse, and it's where he may have been poisoned himself.
One theory is his daughter somehow unwittingly brought the poison with her from Moscow. But the police are saying very little publicly - not until they can be certain who did this and how.