East of England Ambulance Service spokesman said its resources have been "stood down from the scene":
Sadly, it is believed that four people in the helicopter are believed to have died in the crash. Ambulance resources have now been stood down from the scene.
Our thoughts are with the family and friends of those who have lost their lives tonight.
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It comes after security was stepped up around the country following the Manchester Arena attack which killed 22 people.
A murderer nicknamed 'Houdini' after escaping the death penalty seven times has been given the lethal injection.
The distress signal sparked a police hunt in the area to find the person or group who made it.