A police investigation is underway after the sudden death of a 24-year-old woman in Clayton-le-Woods.
Emergency services were called to an address on The Martindales around 4.30pm on Sunday, December 10.
The woman was pronounced dead at the scene by paramedics and a 27-year-old man was arrested on suspicion of murder, police have said.
He has since been released under investigation.
Further tests are being carried out to determine a cause of death.
A spokesperson for Lancashire Police said: "We were called following reports of an incident at an address in The Martindales, Clayton-le-Woods.
"Officers attended and a 24-year-old woman was found unresponsive.
"Sadly she was pronounced dead at the scene by paramedics.
"The death was initially treated as suspicious with a 27-year-old man from Clayton-le-Woods arrested on suspicion of murder. He was later released under investigation.
"Following a Home Office post-mortem further tests will be conducted to establish a cause of death."