This paper performs a forensic investigation to a set of Android mobile applications aiming at discovering sensitive information related to the owner of the mobile device. These applications were chosen based on the fact that: i) they are very popular on Google Play Store, ii) they handle sensitive personal information, iii) they have not been researched by previous works and iv) they are free to download and install. The three chosen applications belong to the following categories: bank, mobile network carrier and public transport. The evaluation of the security of the applications was performed using two techniques: code and disk analysis, as followed in the literature. Based on our findings we derive the conclusion that these applications despite their criticality have failed to incorporate security techniques to protect user's sensitive data and a forensic analysis can reveal crucial and significant information from a forensics point of view.