This is the chilling moment a smiling killer tells police he "knows what happened" as he returns to the scene of a murder he committed just hours beforehand.
Marek Hecko, 26, was jailed for life after stabbing 44-year-old Adrian Ellingford to death at a home in Chelmsford, Essex last summer.
The victim was found with two knife wounds, including one so brutal that it damaged and cut a bone in his chest.
