One of the biggest questions of agglomerations today focuses on the problem of the public transport supply. To deal with this, Bogota has developed a new urban transport system that has had worldwide recognition since 2000: Transmilenio. While most studies have focused on studying the impact of this new public transport system with respect to the environment, hedonic prices, employment and urbanism, among others, none (except one) have studied the question of the evolution of crime linked to the existence of Transmilenio. The aim of this article is to demonstrate that the evolution of urban transport, which is traduced on the construction and on the improvements of Transmilenio, has had a direct impact on the crime rates in the city. By collecting a set of spatially referenced data regarding crimes in 112 of the 117 planning zones that make up the city, this research follows a differences-in-differences methodology to test the causality of the transport system in the evolution of crime rates in each zone for different periods. After a deep descriptive analysis of data and the implementation of the econometric methodology suggested, results indicate that enhancement of the public transport system has had no clear impact on crime rates in all zones of the city. Depending on the zones and on the Transmilenio line in question, the transport system may increase or decrease the number of crimes on each zone beneficiaries or not from the improvement of the system. However, this research gives a non-negligible number of hints to take in consideration on further studies.