Here's what we know so far.
Detective Sergeant Nick Bailey was in intensive care, but is now stable but serious. He is talking, but not out of the woods yet.
Detective Sergeants don't walk about Salisbury very often. We don't even get normal Police about.
So the information that he was the first responder is odd.
The first on the scene were an off duty doctor and nurse, and members of the public. They all helped them into recovery positions, got them breathing again etc. Amazing.
They found out very quickly who Sergei was, or already knew. Because they sectioned off his house pretty quickly. Maybe DS Bailey went to his house? Maybe they were poisoned there?
They have sectioned off his house, his car, the graveyard (where his wife and son are buried), the restaurant and the pub. His journey on Sunday basically.
The 21 treated, are the paramedics, police, and members of the public who came into contact with them, and had a range of advice and treatment (blood tests) etc.
Where DS Bailey was will be key to working out where the poison came from, how it was issued.