Free-floating bike sharing (FFBS) is an innovative bike sharing model. FFBS saves on start-up cost, in comparison to station-based bike sharing (SBBS), by avoiding construction of expensive docking stations and kiosk machines. FFBS prevents bike theft and offers significant opportunities for smart management by tracking bikes in real-time with built-in GPS. USF, collaborated with Social Bicycles, launched a free-floating bike sharing program in 2015, named Share-A-Bull. This study analyzes historical biking trajectory data of bike sharing users for understanding their mobility patterns and the correlation with environment variables and the interactions of those variables. The outcomes provide insights on system design and operations. In addition, we extract and identify users who are deliberately mishandling or damaging bikes in a free-floating bike sharing system based on its historical data. A four step method is developed to solve this problem and illustrated with the case study of Share-A-Bull bike sharing program.