A man swimming in the Red River in Grand Forks just before the noon hour touched off the search for a woman also believed to be in the water.
The man was sitting on the bank of the river when officers arrived.
The 54-year-old was taken to Altru.
A woman claimed she believed a female had also entered the river.
Officials conducted a search but there was no evidence to indicate anyone else had entered the water.
The search was suspended around 12:45.