The people who partake in corruption have an incentive to hide their illicit behavior. This represents a strategic challenge to law enforcement officials across Latin American cities. A related concern is that formal claims submitted to a city's anti-corruption agency are seldom analyzed in a systematic manner. We respond to these challenges by examining a unique (and anonymized) dataset containing 445 claims collected by an urban district government in central Mexico. First, we propose a novel typology of urban corruption, which can later be applied to analyze corruption-related claims elsewhere. As a next step, we apply this typology to study the claims submitted to the district government in question. Large agencies and the agencies responsible for regulating the construction sector are found to be most vulnerable to corruption. The district as a whole also comes across as lacking in transparency and as struggling with bribery and kickback schemes.