(CBS) – The 20-year-old driver who died when a car plunged into a roadside pond Saturday night was a single mother who leaves behind an infant boy – and a devastated family.

CBS 2’s Dana Kozlov reports.

Emory Diaz-Sepulveda was mother to a 3 ½-month-old baby named Roy. He’ll never know his mom now, after the accident off Interstate 88 in Aurora.

Diaz-Sepulveda’s family can’t quite absorb the loss yet. They aren’t sure why the young woman’s car went off the I-88 ramp at Eola Road and plunged into a retention pond around 7:30 p.m.

Three of her passengers, including an adult woman and two minors, were rescued. But firefighters spent hours chopping away at the ice and diving trying to locate her; they found her body about seven hours later.

“We’re thinking she just might have lost control or might have missed the exit at the last moment,” Diaz-Sepulveda’s aunt, Margot Delgado, tells CBS 2.

On Sunday, personal items belonging to those in that car lay scattered near the side of the pond.

Illinois State Police will only say the investigation continues. The grief for this family is just beginning.

Family members say Diaz-Sepulveda moved to the U.S. from Puerto Rico about three years ago. She had lately been living in DeKalb.

Her mother was flying into Chicago, and then the family plans to go to police to try and learn more.