A speeding stolen car smashed into a bus on an interstate in San Antonio on Thursday, causing a multi-vehicle crash that left four people dead and more than a dozen injured, police said.

Police said two people traveling on the bus were pronounced dead at the scene on Interstate 35 and another two were declared dead in a hospital. Fire officials said they took 21 people to hospitals.

Several people fled the stolen Camaro without stopping to help, including at least one who was armed, police said.

Police Chief William McManus said children and older people were among the injured.

The Camaro struck a trailer attached to the bus, causing the bus driver to lose control of the vehicle, which then bounced into a guardrail. A tractor-trailer then smashed into the bus, which rolled onto its side. Several people were ejected from the bus, police said.

Moments after the crash, four suspects were seen getting out of the Camaro and running from the scene, police said.

The shuttle had departed from Fort Worth and was headed to Eagle Pass. 

Shuttle company owner among victims

The company that was operating the shuttle bus, Transportes Guerra, is based in Fort Worth. 

CBS News Texas spoke with the family who runs the business and confirmed that the owner, Jose Hector Guerra — also known as "Tito" — was among those killed. He leaves behind a wife and children.

Security video shows theft of Camaro 

After the crash, surveillance video of suspects stealing the Camaro.

Investigators say the car was stolen Monday morning. The video shows two men forcing their way in, using a screwdriver before driving off.