The San Antonio Fire Department is investigating exactly how a woman was able to drive off in one of its ambulances Wednesday, taking two staff members and a patient along with her on a 22-mile-long ride.

Alecsis Skie Roberts, 30, was arrested by San Antonio police Wednesday after they boxed in the stolen ambulance near Highway 90 and Southwest Military.

Police say Roberts had jumped into the driver's seat as EMT workers tended to a 65-year-old patient in the back of the ambulance.