Police say a 21-year-old man from Dartmouth was found at the scene, bleeding from the facial area.
The man was transported to the QEII hospital, where his medical condition eventually worsened.
Police obtained a description of possible suspects and a vehicle involved in this incident.
Approximately three hours later, officers responded to another unrelated call, and stopped a similar vehicle attempting to leave the altercation.
Police say an 18-year-old man from Dartmouth is being held in custody, facing charges of aggravated assault, robbery, and two counts of breach of probation.