A 22-year-old mother found dead in the back garden of her home died from severe head injuries following a "sustained attack", police have said.
The body of Emma Baum, who lived with her two-year-old son Steffan, was discovered in the village of Penygroes, Gwynedd, on Monday.
Officers from North Wales Police were called to the scene in Llwyndu Road at 10.45am - when the body was discovered - but had visited the area earlier following a report of a possible disturbance shortly after 4am.
Neighbours said they heard a female screaming in the vicinity of the address at about 4am but police said they found nothing suspicious and left. The matter has been referred to the Independent Police Complaints Commission (IPCC).
Detectives are to seek a warrant from magistrates for further time to question a local man arrested on suspicion of murder.
A woman arrested on suspicion of perverting the course of justice and assisting an offender has been released on bail pending further inquiries.
Detective Superintendent Iestyn Davies, the man leading the investigation, said: "Emma died as a result of severe head injuries following a sustained attack.
"I cannot at this stage release any further details about the specific injuries but I believe that the attacker would have been bloodstained. There is a strong possibility that the person responsible has discarded clothing after the assault and I would appeal to anyone who may have found items of clothing discarded to come forward.
"It is apparent that a bladed item was used and again this may have been disposed of. I cannot provide any details regarding the type of bladed item.
"We have a number of reported sightings of a person running from the rear of Emma's house. I believe this to be a male person who was wearing a dark possibly grey-coloured hooded top and dark tracksuit bottoms.
"This person ran along the rear of Llwyndu Road and in the direction of King's Road. This was at about 4am but I believe that the person responsible had been in the vicinity of Llwyndu Road from about 2.30am onwards.
"Again I would ask for anyone who has seen someone matching that description to come forward."
On Wednesday, Ms Baum's mother, Amanda, said her daughter had "a heart of gold and would do anything for anybody".
Anyone with any information should contact the Major Incident Room on 101 or alternatively call Crimestoppers anonymously on 0800 555 111 quoting reference U105426.