Senior inspector Frank Stolte, played by Johannes Brandrupp
, is the first detective to appear in the series, alongside his assistant Ingo Fischer. He was formerly a member of the Grenzschutzgruppe 9, namely, the antiterrorist unit of the Bundeskriminalamt agency of the federal police of Germany but was transferred for insubordination. Initially, his colleague was Ingo Fischer and his boss was Katharina Lamprecht. From the 3rd episode, because of the tragic death of Ingo, his new sidekick was a young turk, Semir Gerkhan. Frank is very determined but is very sensitive and shy, as well as having the behaviour to be stone cold. He leaves the service at the end of the 1st season of the series. No one knows the reason for his departure, but it seems that the cause is: one of which being that Ingo was killed, he was afraid that he could meet the same faith as he did. Since then, he served in the military for some time where during one operation, he yet lost another close friend, following these events, he privately investigated a small contraband scheme involving a mysterious figure responsible for his cohort's death when serving in the army. He reappears in the episode ''Risk'', with the help of Semir and his partner at the time, Paul Renner, he is able to close a case and is rescued after nearly getting blown off of the edge of a dam. Semir saves him by grabbing onto his hand to prevent him from falling off. Frank pays Semir with a lot of respect for his aid.
- Weapons:
The only pistol he used was a S.I.G. P225, during the 1st season.
- Vehicles:
He drove an Audi 100 C3, he wrecked her in the episode ''New partner'', while chasing some criminals, after that, he used a B.M.W. 3 E36, which was also driven mutually by Semir, and his successor André Fux.