It happened off the Southwest Freeway near Highway 99. A dive team pulled the vehicle out of the water.
Fort Bend County deputies tell Eyewitness News they believe two people were in the truck.
Deputies also believe the driver left his girlfriend to fend for herself in the passenger seat. She eventually got out on her own. The driver took off running from the scene.
Deputies say they know who the driver is and will charge him with failure to report an accident when they find him.
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