Police initially believed the pair had taken heroin or crack cocaine from a contaminated batch of drugs when they were called to an address in Muggleton Road.
But on the night of July 4, it was confirmed the pair had been exposed to the nerve agent Novichok - a deadly chemical weapon developed by Russia.
On July 13, cops revealed they had found the substance in a bottle at Charlie's home.
What is the latest on their condition?
Defence sources claimed the couple - who have no connections with Russia or security services - were poisoned and samples have been sent to the Porton Down research facility for urgent testing.
Medics confirmed they were contaminated through their hands, and both were rushed separately to hospital.
When Dawn was confirmed dead Charlie was still in a critical condition in hospital.
However, he regained consciousness and his condition was assessed as serious, but stable.
Former Russian spy Sergei Skripal and his daughter Yulia were poisoned by a suspected military nerve agent in Salisbury, which is around eight miles from Amesbury.
Mr Skripal, 67, and his daughter, 33, were left in a critical condition after they were found slumped on a bench in Salisbury city centre on March 4.
They spent weeks in Salisbury District Hospital where they underwent treatment for suspected exposure to the Russian-created nerve agent Novichok.
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