rikkeisiin

Could you clarify what you mean by "rikkeisiin"? In Finnish, the form could be read as an inflected form of a base noun, but there is no widely known concept, place, person, or organization by that exact name. Do you want a linguistic entry describing possible interpretations of the term, a fictional or hypothetical article, or a real entity if it exists? Once you specify, I can draft a concise, neutral wiki-style article under 300 words.