A warning has been issued after envelopes containing white powder were sent to addresses across north Essex.
Essex Police says it has launched an investigation after a number of suspicious letters were received at addresses in the Braintree, Chelmsford and Stansted areas.
Recipients have included a bank, a college, a shopping village and hotels.
No-one has suffered any ill effects but people have been upset and made anxious by the incidents.
Officers at Essex Police say all the letters to date have been harmless but they have urged anyone who receives an envelope that they feel is suspicious to contact police immediately.
They say any item found to contain white powder or other suspicious substance should be left in situ with doors and windows shut while any fans or air-conditioning should be switched off. Anyone who has had contact with the white powder should be isolated until police attend and are able to provide reassurance.
Anyone with information is asked to contact Essex Police on 101 or Crimestoppers on 0800 555 111.
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