Usman was implicated in the FitMart Mall bombing in General Santos on 21 April 2002, which killed at least 15 people and injured 55 others.[4] Several weeks later, he was arrested and accused of assembling the bomb. He was interrogated and imprisoned at the Sarangani Provincial Police Station, but was made a minimum-security detainee for good behavior. His cell was not locked, and he escaped in October 2002.[5]