A pregnant Illinois mother crossing the street with her fiance was mowed down and killed by a woman in a Land Rover, who claimed to police that she had no idea what she hit, according to local investigators.

It wasn”t until after the woman allegedly saw reports about the victim’s death that she realized it was a person, cops say.

“All I heard was a smack,” recounted Charlie Walkanoff, fiance of victim Michelle Heidbrick, in an emotional interview with local CW affiliate WGN.

“Next thing I knew, she’s rolling down the street,” Walkanoff said, crying. “They hit my baby so hard. I was trying to yell to get people to call 911, and someone stopped, and they did.”

Rosalinda Vaca, 49, is charged with leaving the scene of an accident involving death, a felony, in connection with the Sunday night hit-and-run incident in Waukegan, according to online court records. Her black 2016 Land Rover SUV was seized by police and is being looked at as part of the still-ongoing investigation, per the Lake and McHenry County Scanner. Heidbrick’s unborn baby was killed as well.

Police reportedly questioned Vaca about what happened and she allegedly admitted to knowing she struck something on Sunday night in the area of Grand Avenue and Jackson Street, but she claimed she had no idea what it was.

It wasn’t until after Vaca caught wind of Heidbrick’s death in the same area that she realized what happened, according to police.

“She just turned five months on Sept. 19,” Walkanoff told WGN about the couple’s unborn child.

“My baby didn’t deserve to die that way,” he said.

Vaca reportedly surrendered to Waukegan police on Tuesday after hearing the news. A witness allegedly identified her and the Land Rover she was driving on Sunday night when she slammed into Heidbrick as she was crossing the southbound roadway of Grand Avenue, per WGN. The witness confirmed that Vaca allegedly refused to stop and kept driving.

Heidbrick leaves behind an 18-year-old son who reportedly just started college. Her sister said in a GoFundMe description that Heidbrick was “pronounced dead at the scene from the injuries she sustained.”

Heidbrick’s family told WGN that they are “absolutely heartbroken” by what happened and are awaiting the results of the investigation to see if additional charges will be filed.

Vaca was behind bars Wednesday awaiting her detention hearing.