Late Wednesday evening, police released the name of the 7-month-old who died when his dad's car ended up in the River Des Peres.
Trenton Payne of St. Louis was found, still strapped into his car seat, in the back.
His father, a 24-year-old man, was taken to the hospital in critical condition. He wasn't breathing when rescuers pulled him from the sinking car.
It's unclear how long the car was underwater. A passer-by says that when he saw the car, it was already sinking.
"The back of the car was out of the water and bubbling and as soon as I saw that, I called 911," said Todd Gilliam.
Todd was driving along the 6000 block of River Des Peres when he spotted the car - around 1:30 this afternoon. He says he spent minutes trying to flag someone down to watch his three year old daughter - so that he could dive into the water.
Gilliam said that when the first rescue crews got to the scene, he swam in.
Police say two citizens and a police officer helped get the driver out of the vehicle. Gilliam described one of the rescuers as a firefighter. Gilliam says the men used a knife to cut through a seat belt and pull the adult victim from the car.
Gilliam says the water was cold and murky. He says they didn't see anyone else in the car. Later, the fire department's rescue team would find Trenton in the backseat.
Police do not know what caused the car to go into the river. At the scene, the chief of the St. Louis Fire Department told me they couldn't find anyone who witnessed the car going into the water.
The police accident reconstruction team says it could be weeks before they know what happened. Investigators will look at everything from tire tracks and trajectory to the driver's medical history and toxicology results.
The name of the driver has not been released.