Two horse riders were seriously injured and their animals later put down after a crash with a van.
Ambulances sent to Woodgreen Road, Waltham Abbey, on Friday, drove the two injured riders to Royal London Hospital for treatment.
An Essex Police spokesperson confirmed the driver of the van is a woman in her 30s who was driving a Volkswagen Crafter.
They said she was not arrested but was stopped and reported for careless driving.
Police say they are investigating the cause of the collision, and that the Crown Prosecution Service will make a decision about whether she is to be charged.
Anyone with information should get in touch by quoting incident 350 and calling 101, can contact Crimestoppers anonymously on 0800 555 111.
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