What is {cause of death} of {William McKinley} that is {instance of} is {attack} ?
What is { cause of death } of { William McKinley } that { instance of } is { attack }?
SELECT ?obj WHERE { wd:Q35041 p:P509 ?s . ?s ps:P509 ?obj . ?s pq:P31 wd:Q81672 }
select distinct ?obj  where {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q35041> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P509> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> ?obj .
?statement <http://www.wikidata.org/entity/P31> <http://wikidata.dbpedia.org/resource/Q81672>
} 

What kind of attack caused William McKinley to die?