Wadea Al Fayoume, 6, poses in an undated family photograph. File / Reuters

In the Chicago-area case, officers found the 32-year-old woman and boy late on Saturday morning at a home in an unincorporated area of Plainfield Township, about 65 kilometres southwest of Chicago, the Will County Sheriff's Office said in a statement on social media.

Relatives and a Muslim civil liberties and advocacy group identified the slain boy as the wounded woman's son. Authorities did not release the names of the two victims.

But the boy's paternal uncle, Yousef Hannon, spoke at a news conference on Sunday hosted by the Chicago chapter Council on American-Islamic Relations where the boy's father was in attendance.

There the boy was identified as Wadea Al Fayoume, a Palestinian-American boy who recently had turned 6. The organisation identified the other victim as the boy's mother.

"We are not animals, we are humans. We want people to see us as humans, to feel us as humans, to deal with us as humans, because this is what we are,” said Hannon, a Palestinian American who emigrated to the US in 1999 to work, including as a public school teacher.

The Muslim civil liberties organization called the crime "our worst nightmare” and part of a disturbing spike in hate calls and emails since the outbreak of the Israel-Hamas war. The group cited text messages exchanged among family members that showed the attacker had made disparaging remarks about Muslims.

"Palestinians basically, again, with their hearts broken over what’s happening to their people,” said Ahmed Rehab, the group's executive director, "have to also worry about the immediate safety of life and limb living here in this most free of democracies in the world."

The boy was pronounced dead at a hospital. The woman had multiple stab wounds and was expected to survive, according to the statement. An autopsy on the child showed he had been stabbed dozens of times.

"Detectives were able to determine that both victims in this brutal attack were targeted by the suspect due to them being Muslim and the on-going Middle Eastern conflict involving Hamas and the Israelis,” the sheriff's statement said.

According to the Will County sheriff’s office, the woman had called 911 to report that her landlord had attacked her with a knife, adding she then ran into a bathroom and continued to fight him off.

The man suspected in the attack was found on Saturday outside the home and "sitting upright outside on the ground near the driveway of the residence” with a cut on his forehead, authorities said.

Joseph M. Czuba, 71, of Plainfield was charged with first-degree murder, attempted first-degree murder, two counts of hate crimes and aggravated battery with a deadly weapon, according to the sheriff's office.

Attempts to reach Czuba or a family member were unsuccessful Sunday. His home phone number was unlisted. Messages left for possible relatives in online records and on social media were not immediately returned.

The sheriff’s office and county public defender's office did not immediately return messages about Czuba's legal representation.