A man and woman have been found dead with stab wounds inside their home in Blackburn.
Police were called to the terraced property on Hardman Street at 8.22am on Monday after reports that two people had been injured.
A large police cordon was quickly put in place around the house after the pair were found inside and pronounced dead at the scene.
A forensic tent was also erected outside the front door, before several back alleys were sealed off as detectives continue to investigate.
A man in his 40s has since been arrested on suspicion of murder and remains in custody.
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Lancashire Police said they do not believe there is any wider threat to the community.
Neighbours woke to a major police presence as detectives carried out door-to-door enquiries.
Police said the pair had not yet been formally identified and post-mortem examinations would take place in due course.
Detectives are also working to establish what happened and why, with the motive still unclear.
A police spokesperson said: ‘We are at the early stages of establishing exactly what has occurred and why.
‘Detectives are continuing to work to establish a motive for this tragic incident; however, we don’t believe there is a wider threat to the community.’
The force said the police presence in the area would remain increased over the coming days while enquiries continue.
Officers are appealing for anyone who saw or heard anything suspicious in the area over the past 24 hours, or who has CCTV, dashcam, mobile phone or doorbell footage, to come forward.
Anyone with information can contact police on 101, quoting log 0252 of September 7, 2026.
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