In this work, we describe an experiment for evaluating the integrity of election results, and improving transparency and voter participation in electronic elections. The idea was based on two aspects: distributed collection of poll tape pictures, taken by voters using mobile devices; and crowdsourced comparison of these pictures with the partial electronic results published by the electoral authority. The solution allowed voters to verify if results were correctly transmitted to the central tabulator without manipulation, with granularity of individual polling places. We present results, discuss limitations of the approach and future perspectives, considering the context of the previous Brazilian presidential elections of 2014, where the proposed solution was employed for the first time. In particular, with the aid of our project, voters were able to verify 1.6 % of the total poll tapes, amounting to 4.1 % of the total votes, which prompted the electoral authority to announce improved support for automated verification in the next elections. While the case study relies on the typical workflow of a paperless DRE-based election, the approach can be improved and adapted to other types of voting technology.