North Wales police investigating a house fire urged people who filmed the blaze to hand the footage over to detectives.
Four members of the same family were killed in the inferno in Maes Y Groes, Prestatyn.
Steve Allen's son Bailey, four, and daughter Skye, two, died in the blaze last Friday night, alongside Mr Allen's sister Lee-Anna Shiers, 20, and her 15-month-old son Charlie.
Firefighters rescued Charlie and his dad Liam Timbrell, 23, from the first-floor flat but the youngster died later.
Mr Timbrell is still in hospital.
Detective Superintendent John Chapman said: "I am particularly eager to hear from anyone who was in Maes y Groes after the fire had started to possibly offer assistance and may have filmed the scene on their mobile phone or other electronic device."
Anyone with any information is asked to contact North Wales Police on 101 or anonymously via Crimestoppers on 0800 555-111.