A teenager has been arrested over the death of his father and the stabbing of his mother.
Police were called by the ambulance service to an address in Blackburn at 7.50am on Friday following reports a man and woman had been stabbed.
The man was found dead at the scene in Heys Close and the woman was taken to Royal Blackburn Hospital.
A spokesman for Lancashire Police said: "At this stage it is thought that the man is 46 years old and the woman is believed to be 41 years old.
"An 18-year-old man has been arrested on suspicion of murder in connection with the incident and is currently in police custody."
Sources said the man arrested was the son of the couple and that the incident was domestic-related.
The couple were named locally as Neil and Deborah Ryan.
Their son, Jordan, is understood to be in custody after being arrested earlier at the nearby home of his grandparents.
Police said Mrs Ryan's injuries are not thought to be life-threatening.
Detective Superintendent Ian Critchley said: "This is clearly a tragic case for the family and our main concerns are with them."
