Question: who was the killer in and then there were none book
[{'answer': 'Justice Wargrave', 'provenance': [{'wikipedia_id': '18949410', 'title': 'And Then There Were None', 'start_paragraph_id': 7, 'start_character': 62, 'end_paragraph_id': 7, 'end_character': 78, 'bleu_score': 1.0, 'section': 'Section::::Plot summary.\n'}]}]