Detectives investigating a house fire in which four siblings died have re-arrested a teenager in connection with the investigation.
Dyson Allen, 19, has again been arrested on suspicion of murder and is in custody.
He is being held for questioning over the blaze at a converted bungalow in Freckleton, Lancashire, which killed siblings Reece Smith, 19, four-year-old twins Holly and Ella Smith, and Jordan Smith, two. He was initially arrested in January and then bailed pending further inquiries to an address outside Lancashire.
A major investigation was launched after emergency services were called to the house on Lytham Road following a report of a fire just before 11.30pm on Saturday January 7. The four siblings were taken through to hospital following the fire but died later.
Detective Superintendent Dermott Horrigan said: "This is an extremely tragic and complex case and detectives have, over the past 11 months, been working tirelessly to try and piece together what happened that night, which has resulted in this latest action.
"The investigation is continuing and if anyone thinks they have any information that they think may be useful and have not yet come forward, I would urge them to do so."
The fire began inside a wardrobe in one of the upstairs attic bedrooms at the house. The victims' mother, Michelle Smith, 36, who has five other children, was led out of the house by firefighters.
The blaze took hold hours after the family held a party at the house to celebrate her birthday. Post-mortem examinations showed that each victim died as a result of the effects of inhaling smoke.
Police said the victims were in two separate attic rooms at the property, which suffered limited fire damage but extensive smoke damage. Smoke detectors were installed at the house but were not in working order.
Police said that it "became clear" once fire investigators analysed the scene that the blaze was not accidental, though it is not believed and accelerant such as petrol had been used.