Coventry police have warned robbers who stole 20kg of silver from a factory could be killed by their proceeds as it contains a potentially lethal dose of cyanide.
Four masked men forced their way into an electroplating factory in Coventry just after 5.30pm on Monday 12 January before stealing up to 20 bullion bars - each weighing a kilogram - dipped in a solution containing cyanide.
Detectives have warned the thieves, as well as those who might come into contact with the haul, of "nasty" burn-like rashes and in the case of ingestion, death.
Detective sergeant Dean Jones, from Coventry's acquisitive crime team, said: "The company tell us that the solution used for electroplating is extremely toxic; the thieves may not be aware of the danger it poses and the unsuspecting public need to be made aware in case the thieves try to sell the silver on.
"If anyone has come into contact with the silver bullion the immediate advice is to rinse with fresh water and seek medical attention."
Cyanide - natural, combustible or genocidal weapon?
Cyanide is is a rapidly acting, potentially deadly chemical that can exist in various forms.
It is released from natural substances in some foods and in certain plants, given off when plastics are burned and was fatally used as a genocidal agent by the Nazis in World War II.
Exposure to a large amount of cyanide can cause convulsions, loss of consciousness and respiratory failure leading to death.