We construct a one-shot corruption game with three players, a briber who can decide to bribe or not, an official who can reciprocate or not and an inspector who can decide to inspect or not. We employ four penalties that can be distributed asymmetrically, making it possible to punish bribing and bribe-taking as well as reciprocating and receiving reciprocation to different degrees. Penalties apply if corruption is detected. The probability of detection is endogenised, as it depends on inspection. The model differs from other inspection games in that the offence (corruption) can only be completed through a joint effort of the two offending players. This leads to surprising results, especially in conjunction with asymmetric penalties. First, in contrast to Tsebelis' results, we find that, with endogenous detection, higher penalties do reduce the overall rate of offence. Second, this result holds only if the penalty for reciprocating on the official is raised. Surprisingly, and unlike other asymmetric penalty prescriptions in the corruption literature, higher penalties on the briber have the opposite effect. They may reduce the probability of bribery, but they also increase the probability of reciprocation to the extent that the overall probability of reciprocated bribery is increased.