Question: Why did Letita McTavish Hargrave and Sextus Barbour die?
SPARQL:
 SELECT DISTINCT ?uri WHERE { <http://dbpedia.org/resource/Letitia_MacTavish_Hargrave> <http://dbpedia.org/ontology/deathCause> ?uri. <http://dbpedia.org/resource/Sextus_Barbour> <http://dbpedia.org/property/deathCause> ?uri}