A company is fighting a legal case in a country where a judge investigates the facts and juries are rarely used. Which legal system is being used?

Canon law refers to the body of laws and regulations developed or adopted by ecclesiastical authority, particularly in the Roman Catholic Church. It does not pertain to a national legal system governing civil matters or fact-finding procedures in courts, thus making it an irrelevant choice in this context.

Customary law is based on the traditions and practices of a particular community or society. While it may involve local customs in legal decision-making, it is often less formal and more variable than civil law, which is structured around codified statutes and does not typically feature judges investigating facts.

Common law systems, primarily used in countries like the United States and the United Kingdom, rely heavily on precedent and jury trials. Judges in common law jurisdictions generally interpret existing laws rather than investigating facts, making this choice inconsistent with the scenario described in the question.