Graciela Martinez Dead: Teen Found In Car She Couldn't Get Out Of

A 14-year-old girl was found dead inside a car that investigators said she couldn't exit.

Graciela Martinez was found dead inside her brother's BMW on Wednesday. The car was parked outside Madera South High School in Madera, Calif, according to KMPH.

"She was a nice person. She came from school and then [went] to work, and the after work she would help my mom around the house," Martinez's sister, Patricia, told the station. "She didn't have... problems in school or anything."

Authorities told ABC News that faulty locks in the car likely caused Martinez's death after she was unable to get out of the vehicle.

Police said Martinez is thought to have fallen asleep in the car on Wednesday morning. She likely woke up and realized she was trapped inside.

"It appears there may be a defective locking system on the car, but we still need to do further tests to determine if that’s true and correct,” Det. Robert Salas said.

KFSN reports that autopsy results suggest Martinez died from "environmental hyperthermia" or heat stroke.