Just One Case is the twenty-eight episode of the anime.
Schuwald tells Richard Brown that he wants him to stop investigating Edmund Fahren's death after finding out that Karl is his son. Brown learns that a "Johan" is now working with Schuwald. On his way home, at the U-Bahn, Brown senses someone is trying to push him to the tracks. One night, Richard feels he might be being followed.
After reviewing the Stefan Joos cases files, Richard tells Dr. Reichwein that he thinks all those murders might actually be a single case. Richard starts re-investigating the cases and interviewing people related to the victims. All of the cases seem to be connected to Mr. Schuwald and Richard concludes that those murders were committed in order to isolate Schuwald.
During the day, Richard's life seems to be threatened several times as if someone was trying ti kill him making it look like an accident.
Dr. Reichwein tells Richard that he recevied a letter from Rudy Gillen, a former student of his, who says that he interviewed a criminal who said that he killed someone because a friend asked him to. Reichwein mentions that this friend's name was Johan.
Reichwein and Richard conclude that, if they are right, Johan has, indeed, ordered those murders for the past four years to isolate Schuwald. They even deduce that the apparent suicide of Edmund Fahren, who claimed to be Schuwald's son, might be related to Johan.