It happened around 9:41 a.m. on the southside of the Chesapeake and Delaware Canal, roughly one mile west of William V. Roth Jr. Bridge.
The three who perished in the crash include an 18-year-old male driver and his relatives, a 16-year-old boy and a 12-year-old boy.
A 6-year-old boy, who is also related to the driver, still remains missing. Police said a 16-year-old girl survived the crash.
Delaware State Police said the teen driver, traveling in a Chevy HHR, managed to get out of the vehicle and saved the girl who was also a passenger. He then went back to save the others but he died in the process.
"The lone survivor is a 16-year-old female," said Master Corporal Michael Austin of the Delaware State Police, adding this about the driver: "He was a hero he tried to do everything he could to get the remaining passengers in that vehicle."
18 yr old male driver is confirmed dead, 16 yr old female passenger survived and 3 males who were in the vehicle when it went into the water are unaccounted for. The vehicle is located and crews are working to pull it out of the water. https://t.co/t7KSAhJPPg— Annie McCormick (@6abcAnnie) October 6, 2019
The gray vehicle was pulled from the water during a search and recovery operation in the C&D canal in Middletown DE. 18 yr old driver is confirmed dead, 6,12,16 y/o male passengers are unaccounted for and a 16 y/o girl survived. pic.twitter.com/GgSx7Qef8B— Annie McCormick (@6abcAnnie) October 6, 2019
The bodies of the 16-year-old and 12-year-old victims were both located inside the vehicle when it was pulled from the water just after 6 p.m.
It's still unclear what caused the vehicle to enter the water.
A number of relatives waited at the scene for most of the day and tried to make sense of the tragedy.
"He made a wrong turn. He made a wrong turn and then something must have happened when he was turning around and they ended up in the water," said family member Rudolph Jones.
Family members did not want to identify the victims until all next of kin are notified
Delaware State Police say the victims lived in New Castle and Wilmington in Delaware.
Anyone with any information is asked to call police at 302-365-8486.