The eyewitness's detailed and consistent account of the incident added _______ to the investigation. (credible)

根据题目要求，需将“credible”转化为名词形式填入句子。原句为： "The eyewitness's detailed and consistent account of the incident added ___ to the investigation." “Credible”意为“可信的”，其名词形式为“credibility”，表示“可信度”。将“credibility”代入后，句子变为： "The eyewitness's detailed and consistent account of the incident added credibility to the investigation." 此句语义通顺，符合上下文逻辑。 答案：credibility