San Antonio police and Immigration and Customs Enforcement agents are searching for at least a dozen people on the East Side -- all believed to be undocumented immigrants.
They've captured one person so far.
The search stems from a rollover wreck on Interstate 10 near W.W. White around 9:30 a.m. on Friday.
Using San Antonio police's Blue Eagle helicopter and an extensive ground search, officials said one of the reasons they put so many resources on the search is that the people they're looking for could need help.
"First and foremost, we're trying to find out if anyone was injured in the crash," said San Antonio police Sgt. Javier Salazar. "My understanding is that it was a pretty significant crash, and some of the officers were commenting to me that they're surprised that there was nobody who stuck around who was injured."
Police did catch up to one person who Salazar said didn't have obvious injuries and is in the country illegally. ICE agents say that man has been deported once before.
Salazar said some of the people who ran could be victims.
"(With) San Antonio being what we call a 'gateway city,' many times you'll find human traffickers running their cargo through here, which consists of human beings that have found themselves victims of this trade," Salazar said.
Police combed through areas near the crash site, hoping to find the estimated dozen other passengers who fled, but they also say they'll be on the lookout for any of them to show up at area emergency rooms with injuries from the crash.