Mintach

Mintach acted as the press secretary and representative for Congressman Joseph Boltzmann, who was a member of the German Parliament under suspicion for having killed callgirl Erika Lemser following a purported affair with her. Doggedly convinced of his boss' innocence and trusting him to no ends, he sharply criticized the BKA handling of the investigation, especially on the part of Inspector Lunge. He grew especially angered and deeply perturbed by Lunge's intimations that implicated him in trying to orchestrate a cover-up of his boss' affair. Driven to the brink of desperation by Lunge's zealous and obsessive behavior during the investigation, specifically his unfeeling insensitivity, he committed suicide, still apparently firmly convinced that his boss was absolutely innocent, per his suicide note.

As a result of losing a valuable reference and potential information source in the case, the BKA station chief and his subordinates removed Lunge from the case, ultimately leaving only the case of the Middle-Aged Couple Murders under his exclusive purview, which he pursued with increasingly marked conviction as he narrowed his sights on Kenzo Tenma, the chief suspect in the murders (actually being committed by Johan Liebert and his associates).

(Source: Monster Wiki)