Question: who was the abolitionist captured at harper's ferry virginia
[{'answer': 'John Brown', 'provenance': [{'wikipedia_id': '19825348', 'title': "John Brown's raid on Harpers Ferry", 'start_paragraph_id': 0, 'start_character': 0, 'end_paragraph_id': 0, 'end_character': 10, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]