A man is in a critical condition in hospital after being injured in a hit-and-run incident.
At around 9.40pm on Friday night police received a report that a 42-year-old man had been hit by a vehicle on Seaham Road, in Houghton, which has then driven away from the scene.
Emergency services attended the scene and the man was taken to hospital with life-threatening injuries.
He remains in hospital in a critical but stable condition.
A short time later at around 11.25pm police received a report of a disturbance at an address in nearby Queensway, also in Houghton.
Officers attended and found that three men had entered the address and assaulted a the male occupant of the address before fleeing the area.
Inquiries are ongoing to establish the circumstances around what has happened but police do believe that the two incidents are linked.
Those involved in both incidents are believed to be known to each other and five people have been arrested.
Two of those people remain in police custody at this time, two have been released without charge and one has been released under investigation.
Detective Chief Inspector Lee Gosling said: "We are treating these incidents as linked and do believe that those involved are known to each other.
"Our investigation into what has happened is still ongoing but we do need to hear from anyone who witnessed either of the incidents in question.
"The collision on Seaham Road in particular occurred in the presence of a number of members of the public and we would ask anyone who hasn't already spoken to our officers to get in touch.
"Extra officers have been on patrol in the area to carry out inquiries and to reassure any members of the public concerned about the incidents."
Those with information about the incident, or the people involved, are being urged to contact police on 101 quoting log 1159 02/06/17 or Crimestoppers anonymously on 0800 555 111.