Two men have been stabbed during an incident at an address in Nettleton Road in Gloucester last night.
Police rushed to the scene at 8.55pm.
Two men, aged 30 and 47, suffered stab wounds and were taken to Gloucestershire Royal Hospital.
The 30-year-old man was later transferred to Frenchay Hospital in Bristol and is currently described as being in a critical but stable condition.
The 47-year-old man was later discharged and was arrested on suspicion of causing grievous bodily harm. He remains in police custody at this time while inquiries continue.
The crime scene is this morning cordoned off. Nettleton Road and part of Russell Street will be closed for several hours, although the nearby car park will remain open to motorists.
Police are eager to hear from anyone who was in the area or at the scene at the time of the incident.
Anyone with information is urged to call 101, quoting incident 418 of January 13.
It comes just two weeks after resident John Paul Stewart was found dead at a nearby property, also in Nettleton Road, after paramedics said he had suffered a heart attack. The death was not being treated as suspicious.
Did you see the police commotion yesterday? E-mail reporter Mike Wilkinson at email@example.com or call 01452 698817.