Giebel

Giebel was a major business figure residing in Hamburg, Germany, who, due to a grievance of estrangement with his aunt, murdered her. As a result, his crimes were conflated with the broader Middle-Aged Couple Murders occurring throughout Germany, which had been attributed to Dr. Kenzo Tenma (and were in fact being conducted by Johan Liebert and his accomplices), and Inspector Heinrich Lunge was assigned to investigate the crimescene by the BKA.

Though increasing evidence indicated that neither Tenma, nor anyone involved in the Middle-Aged Couple Murders, was involved in the crime, Lunge had no interest in apprehending the actual responsible party, sensing an opportunity to finally capture his long-time quarry and obsession, Tenma, by making him believe that his "alternate personality", Johan, had in fact committed the crime and thereby attracting him to the residence of Giebel's aunt. Still, Lunge questioned Giebel in an unnerving manner, implying that he was the guilty party, likely to toy with him. Giebel vigorously and angrily denied his guilt and repeatedly asserted his innocence, but his pleas fell on deaf ears, since Lunge viewed him as a means to an end.

However, the increasingly desperate Giebel, believing that Lunge was obsessed with apprehending him, followed him when he went to apprehend Tenma at his aunt's home, and, as he moved in to capture Tenma, delayed Lunge by stabbing him, proving his guilt. However, the determined and impassive Lunge merely shoved Giebel aside contemptuously, before pursuing Tenma. The stab wound could have proved fatal were it not for Tenma's later intervention when Lunge faded out of consciousness from blood loss. Lunge's boss indicated that Lunge's efforts had helped them identify and capture Giebel, while Tenma had escaped.

(Source: Monster Wiki)