https://www.blackhat.com/docs/eu-15/materials/eu-15-Blanda-Fuzzing-Android-A-Recipe-For-Uncovering-Vulnerabilities-Inside-System-Components-In-Android-wp.pdf
It'd be worth checking out retrospectively. They may have been using some DOS exploit in order to prevent logs from being written.
Fuzzing is more for finding flaws in the binaries of a program. A packet analyzer like Wireshark would be needed to see if there was any suspicious web traffic.