How many {killed by} are for {Giovanni Falcone} ?
What number did Giovanni Falcone murder?
How many were killed by Giovanni Falcone?
SELECT ( COUNT ( ?x ) AS ?v ) { resource:Giovanni_Falcone property:killed_by ?x }
SELECT (COUNT(?obj) AS ?objs ) {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q207073> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P157> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> ?obj .
} 

SELECT (COUNT(?obj) AS ?value ) { wd:Q207073 wdt:P157 ?obj }
5