Tension arises when the minister produces a man, Sergeant Tolt, who knew Allen's wife as well, but it turns out that he is blind (and so cannot identify Claire as a fraud). Tolt mentions possessing photographs of Captain Allen and his wife, so Jonas decides that Tolt must be secretly murdered and the photographs stolen.
The introduction of Sergeant Tolt, his blindness, and the subsequent suspicion surrounding him create tension in the narrative.  Jonas's suspicions stem from Tolt's possession of photos of Captain Allen and his wife, leading to a potential murder plot.