Fort Worth police said a 35-year-old woman died Wednesday evening trying to rescue her stepson at the Trinity Park in Fort Worth.
Officers said the 8-year-old fell into the Trinity River, which runs through the park.
The woman, identified as Dania Martinez, panicked and jumped in to save the boy. Officers said the woman couldn't swim.
Witnesses said a bystander rescued the boy.
Meanwhile, the woman's husband and another bystander pulled her from the water and began CPR.
Paramedics took the woman to Harris Methodist Hospital in Fort Worth, where doctors later pronounced her dead.