Detectives have been granted an extra 36 hours to question a man held on suspicion of murdering a woman on Christmas Day.
Emergency services attended Francis Avenue, Fairbourne, Gwynedd, following reports a 74-year-old woman had suffered serious injuries.
Despite attempts by relatives, police and paramedics to save her, she was pronounced dead at the scene.
A 75-year-old man remains in police custody.
Det Ch Insp Brian Kearney, of North Wales Police, described the woman's death as "truly tragic" and added it was a "very rare type of occurrence in north west Wales".
A major incident room has been set up 50 miles away at Caernarfon police station.
Police family liaison officers are supporting the dead woman's family, the force added.