A man was dangled over the canal at Sandiacre and forced to hand over cash by a gang, police have said.
The man, in his 30s, was approached by three men and a woman at about 10.15am on Wednesday.
One of the men held him over the water and threatened to punch him.
He gave them a small amount of cash and they fled.
The men were all in their 30s and the woman was walking a brown bulldog.
One of the men was shirtless.
Call 101 with information.