Police uncovered about 100 grams of high explosives buried in farmland outside a village house in northern Hong Kong where they had brought one of 10 men arrested in connection with the seizure of a powerful pipe bomb to search for evidence on Thursday, investigators said.Officers also revealed they arrested the wife and mother of the 29-year-old suspect after the search at the house, which police believed was being used as a laboratory for making explosives.The suspect was hooded and chained…