This has happened more than once. Good article covering the basics of what to do to try to keep phone safe.
Malware in the Google Play Store: Enemy inside the gates | TechRepublic"According to an article on arstechnica.com, Google examines all apps uploaded to Play (they use a cloud service called Bouncer to verify new apps against known malware signatures and test them for malware-like behavior). In this instance the BadNews-related apps were clean upon upload. The designers introduced the malware components to these programs several weeks later."