Police are continuing to search for a man feared drowned in the River Thames.
The man, in his 30s, was swimming with another man in a stretch of water called Lulle Brook in Cookham, Berkshire, when he went missing.
Police, firefighters, paramedics and search and rescue teams were called to the river at 19:00 BST on Tuesday.
The second man, also in his 30s, was brought to safety by a member of the public and is in a "serious condition" in hospital, police said.
A third man who went into the water to help was unharmed.
Thames Valley Police said searches started on Tuesday evening and were continuing on the banks of the river and in the water, using specialist teams.
Supt Colin Hudson, said: "Our thoughts are with both the men's families and our officers are supporting them at this very difficult time."