San Antonio police data shows nearly 19,000 car thefts were reported in the city during a recent 12-month period. The thefts were reported in all parts of San Antonio between May 1st, 2023, and May 1st of this year. An undercover detective says most of the thefts took place because people left the cars unlocked, often with the keys inside. These data don't include thefts reported to the Bexar County Sheriff's Office or to the police departments of other cities in the county.