A 16-year-old girl whose body was found burning in an alley in Blackpool had died of stab wounds to the head, a post-mortem has revealed.
Sasha Marsden, 16, a college student and keen dancer from Blackpool, died after sustaining "significant stab wounds" before her body was set alight, it has emerged.
Detectives arrested a man and a woman close to the scene in Kirby Road shortly after the body was discovered, and have been granted more time to question the male suspect, 22, who is being held on suspicion of murder.
A woman aged 22, who was arrested at the same address, has been released without charge.
A police spokesman said: "Following the death of Sasha Marsden, a Home Office post-mortem examination has been carried out and has found that Sasha died as a result of receiving significant stab wounds to the head and face.
"It also showed that attempts were made to set the body on fire and this was after Sasha had died.
"The results have been shared with the family, and specially trained officers are continuing to support them."
The body was found burning in the South Shore area of Blackpool at about 9.15pm on Thursday 31 January.
Hoteliers tried to put out the flames, initially believing they were dousing a mannequin.
Carl Evans, owner of the nearby Kimber Guest House, was among the first at the scene.
Evans said: "I heard the alarms going and saw the smoke, but I thought it was just someone burning rubbish.
"The lass two doors up said someone seemed to have put something out - like a mannequin - but it turned out to be the body of a 16-year-old girl."
Forensic officers are conducting searches of the alleyway, along with rooms inside the Grafton House Hotel in nearby Kirby Road, where the arrested couple were believed to be staying.
Officers are checking local CCTV cameras and carrying out house-to-house inquiries.
Detective Superintendent Andy Murphy said: "This is a murder inquiry and we are dealing with the suspicious death of a 16-year-old girl.
"I would appeal to anyone who was in the area at the time last night to come forward and contact the police. We have a large team of highly trained police officers working on this.
"It is difficult to imagine what the girl's family are going through and we have specially trained family liaison officers working with them to offer them support.
"We will be keeping them informed of the progress of our investigation."
Marsden had recently posted her CV on a jobs website, along with a message. "I am a hard working and honest person," the message read. "I love a challenge and can apply myself to a range of jobs.
"I have a strong sense of responsibility and I'm happy to work on my own or with a team. I consider myself to be very organised and punctual and to be very good with customers and the public."
The incident occurred four months after Marsden went missing for six days in September, sparking a nationwide search by her family.
She was eventually found a week later 300 miles away, in Lowestoft, Suffolk.
Marsden lived with her parents Gary, 42, and Jayne, 45, in the Staining area of Blackpool and was studying childcare at Blackpool and The Fylde College. She also worked in a children's nursery at Blackpool Victoria Hospital.
Mandy Pritchard, head of the college's department for society, health and childhood, said she was "a friendly, considerate individual who cared about her fellow students".
Friends and family paid tribute to Marsden on a Facebook page set up in her memory.