The 32-year-old woman’s house had been on fire shortly before her car was seen entering a lake, 16 miles away.
A father found dead in a burning house in Illinois was shot in the head and a gun has been recovered from the SUV his ex-wife drove into a nearby lake.
The couple’s three-month old baby was pulled from the sinking car after paramedic Todd Zobrist swam out into the chilly water to save him.
The body of his mother, 32-year-old Christy Lynn Campbell, was recovered several hours later.
The car was seen driving down a hill into Silver Lake in Highland about 15 minutes after a fire was reported at the house in Glen Carbon where 37-year-old Justin Campbell was later found dead.
The baby boy, who was initially unresponsive, was floating inside the car.
Mr Zobrist put the infant, Julian Campbell, on the SUV’s roof and carried out CPR, before swimming with him back to shore.
The little boy is expected to recover.
Highland Emergency Medical Services chief Brian Wilson said Mr Zobrist had “definitely saved the child’s life”.
Six of Ms Campbell’s children survived the fire. They will be placed with relatives after being looked after by the authorities.
According to court records, there were several domestic incident reports in the couple’s relationship.
Ms Campbell obtained an emergency protection order against her husband and filed for divorce in 2012, claiming in court papers he “abuses me on a weekly basis”.
She was granted a divorce the following year.