Human Sacrifice in Iron Age Northern Europe
The culture of Bog People. This is a scholarly article but study the contents page and read what you need. An excerpt appears below:
One of the most important questions that should be asked when researching bog bodies that have been appropriated the status of a sacrificial victim is: what evidence is there that a particular case is in fact a human sacrifice and not merely an accidental death, or victim of a non-religious murder or execution? There are a number of
factors which should be considered: probable cause or method of death, position of the body, presence of grave goods, and other less obvious clues such as the stomach contents of the individual.