Two toddlers died in Chicago early Thursday after a woman stabbed a 70-year-old man, left one child in a bathtub, and then jumped from an 11th-floor apartment with her 1-year-old, according to police.

Chicago police are investigating the apparent murder-suicide attempt that took place at a South Shore high-rise building, the Associated Press reports.

They found the woman, who is in her thirties, alive and on the ground with her 1-year-old son just before 2 a.m. Thursday. It was not immediately clear whether the older child was related to the woman, police said.

A security worker at the apartment building took officers to the 11th-floor apartment, where they located the man alive with stab wounds on his face and body.

A 2-year-old boy was found unresponsive in a bathtub with wounds to his head, authorities said.

Chicago Police Department spokesman Anthony Guglielmi called the incident “heartbreaking,” and did not provide further details on the motive of the crime. He said that police are expected to seek charges against the woman if she survives.

“Based on the positioning of the bodies and available evidence ... it appears as though the baby was thrown out of the window and the woman followed. We’re assuming something broke her fall because she survived, which is unusual after falling from that distance,” Guglielmi said, adding that it is unclear if the younger child was also stabbed because of the “trauma from the impact of the fall.”

The man told police when they arrived at the scene that the woman, whom he referred to as his daughter, “began stabbing him and then jumped from the 11th floor with her one-year-old-son,” while the other child was left unattended in the bathtub.

Guglielmi said that detectives believe the woman is in fact the granddaughter of the male victim, not his daughter, and that authorities are “operating under the assumption that these are the woman’s children but need to confirm that.”

Authorities are reportedly contacting other members of the family for additional information. Guglielmi said it is unclear whether the women and children also lived in the apartment, which is the grandfather’s residence, or if they had just been visiting.

The two tragic deaths mark Chicago’s first homicides of the new year.

The woman and the man are both in critical condition at the University of Chicago Medical Center. Both toddlers were pronounced dead at Comer Children’s Hospital, police said.

“It was insanity to me,” a neighbor named Rahin told ABC7 Chicago. “I saw it, it was the first thing I saw when I woke up and it’s right around the corner. I come out here with the dogs at 4 o'clock and I couldn’t believe it.”

If you or a loved one are struggling with suicidal thoughts, please reach out to the National Suicide Prevention Lifeline at 1-800-273-TALK (8255), or contact the Crisis Text Line by texting TALK to 741741