A search is on-going of the Great River Ouse in Bedford after a woman got into difficulties yesterday evening.
Bedfordshire Police were called at 8.06pm and began to search the area off Honey Hill Road.
Officers, the fire service and a police helicopter began the search but the woman, aged in her 30s, was not found.
It is believed she entered the water to help somebody in distress and got into difficulties herself.
Searches by a specialist police dive team are set to continue this morning.
Police are appealing for anyone with any information to call 101 quoting the reference 399 of yesterday.