Question: who was the ice truck killer on dexter
[{'answer': 'Brian Moser', 'provenance': [{'wikipedia_id': '23981878', 'title': 'Dexter (season 1)', 'start_paragraph_id': 8, 'start_character': 294, 'end_paragraph_id': 8, 'end_character': 305, 'bleu_score': 1.0, 'section': 'Section::::Plot.\n'}]}, {'provenance': [{'wikipedia_id': '23981878', 'title': 'Dexter (season 1)', 'start_paragraph_id': 8, 'start_character': 0, 'end_paragraph_id': 8, 'end_character': 757, 'bleu_score': 0.9734732745385111, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 12634854975490981082}, 'section': 'Section::::Plot.\n'}]}]