Rescuers in Hartford said they responded to a report of a swimmer in distress in the water, but found nothing.
The Hartford Fire Department said it arrived on the scene on the Connecticut River near Riverside Park around 8 a.m.
A driver made the emergency call around 7:50 a.m.
Riverside Park is located on Leibert Road.
Hartford's Marine One boat was launched and made sweeps of the area as far south as Wethersfield Cove.
No swimmer was found.
Kayakers in the area also reported that they did not see anyone in the water.
Emergency crews said they cleared the scene around 9:30 a.m.
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