Investigator is a synonym of Detective. Detective is related to Spy. Spy is a type of Investigate. 
Bulk is a synonym of Majority. Majority is a type of Age. Age is related to Candle. you are likely to find Candle in/at/on Dark. 
Investigator <--Synonym--> Detective <--RelatedTo--> Spy --IsA--> Investigate 
Bulk <--Synonym--> Majority --IsA--> Age <--RelatedTo--> Candle --AtLocation--> Dark 