Emergency services including the police helicopter were seen over Bishop Auckland on Monday (May 1) night.
Initial reports suggested that police were searching near the viaduct with eyewitnesses saying the chopper had been scanning the area, but these have not been confirmed by police.
Durham Constabulary has confirmed it attended a ‘disturbance’ in the Bridge Street area of Bishop Auckland, shortly after 7pm.
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One man was arrested on suspicion of public order in connection with an incident last month.
A force spokesperson added: “No-one was injured”.
The County Durham and Darlington Fire and Rescue Service said: "We were called to assist our colleagues at Durham Constabulary just before 10pm last night. Appliances from Bishop Auckland and Durham attended the incident. Fire crews left the scene shortly after midnight.”
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