Why was it in a peat bog?....................
All the other bogs were being used.
From Wikipedia:
Bog bodies have been variously found with cut throats, severed limbs, broken bones, ropes around the neck, entrails pulled through the skin (mega-ouch!!! as per me, not the author), and other marks that suggest the possibility that they were ritually killed or murdered. However, they are also typically found during the process of cutting peat, a form of compressed vegetation that can be used for fuel and other purposes. This situation has complicated archaeologists’ efforts to understand the processes through which a given body came to be in a particular bog, as bodies that are only partially intact may indicate recent damage rather than actions that took place at the time of death.
Well, obviously, it’s a safe place for long-term storage!