Alyssa Mattson, 19, and her baby were pulled from the water by divers after the car crashed into the pond on Forestville Road near Knightdale.
On Thursday morning, the North Carolina State Highway Patrol reported that the 6-month-old died. The condition of the mother is still unknown.
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The incident blocked the 6000 block of Forestville Road on Wednesday evening.
Troopers said Mattson was speeding when she passed another car in a no passing zone, lost control, and skidded off of the road, into the pond - becoming submerged 15 feet deep.
The teen was able to get out and swim to safety.
Mattson and the child were rushed via ambulance to WakeMed; however, the 6-month-old was pronounced dead upon arrival.
Authorities are pulling a car from the water now. We did see an adult and what appeared to be a child pulled from the pond earlier, and rushed inside an ambulance. We don’t know their condition or if they were injured. #ABC11 pic.twitter.com/7cIgPMUgJ4— Elaina Athans (@AthansABC11) March 1, 2018
After pulling the two people from the water, authorities began pulling the car from the pond.
Knightdale spokesman Jonas Silver said the child was in the backseat, in a car seat.
The car was submerged in about 12 feet of water, he said.
Several law enforcement officials near a pond not far from East Wake Middle School. We did see Coroner’s Office leaving in last 10 minutes. Highway Patrol not releasing any info #ABC11 pic.twitter.com/TdJPazq52W— Elaina Athans (@AthansABC11) March 1, 2018
Eight Knightdale firefighters were treated for hypothermia for going into the cold water without protective gear.
A vehicle from the Coroner's Office was at the scene. It later left shortly before 8 p.m.
Several boats could be seen in the water as what appeared to be dive crews worked the scene. Apex firefighters also responded to the incident.
Troopers are still investigating.