A man was arrested on suspicion of causing actual bodily harm after a woman was found with an eye injury at her home in Wisbech.
The victim called 999 at just before midnight and said very little but a man’s voice could be heard in the background.
She asked for police, but the line dropped out before she was put through to officers.
Cambridgeshire Constabulary said they tried to call her back but these attempts failed and, worried for her safety, police visited her home in Wisbech.
When they arrived, a woman with an injury to her eye opened the door.
One man, aged 45, was then arrested on suspicion of causing actual bodily harm (ABH).
He has also been further arrested on suspicion of threats to kill, intentional strangulation and threatening a person with an offensive weapon.
He has been released on conditional bail while investigations continue.
"Did you know that pressing 55 after calling 999 alerts police operators that you need help but are in a situation where you can't talk?" said a police spokesperson.
"Pressing 55 lets the 999 operator know your call is genuine, and they will try to track your location.
"If you can't speak, listen carefully to the questions and instructions from our demand hub call agents so they can assess your call and arrange help."
Find out more info on our website: https://orlo.uk/Silent-999-calls_7C4wD
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