ROCKFORD, Ill. — At least four people are dead and seven others were injured, including one in critical condition, after a man went on a stabbing rampage Wednesday in northern Illinois, authorities said.

Carla Redd, the police chief in Rockford, a city about 94 miles northwest of Chicago, said police received a medical call at 1:14 p.m. Authorities then received additional calls for paramedics and police, who responded to the area and discovered multiple crime scenes.

A suspect was taken into custody and questioned by police on Wednesday afternoon, Redd told reporters on Wednesday. The suspect was later identified as a 22-year-old man.

"This is a pretty painstaking event," Redd said. "My heart goes out to the families right now who are suffering a loss."

Redd noted that not all of the victims were stabbed and none had been shot. The motive behind the attacks remains unknown.

Rockford police later identified the four victims killed as a 15-year-old girl, a 63-year-old woman, a 49-year-old man and a 22-year-old man. Their names were not released to the public.

Three of the four victims who were killed died at the scenes, according to Rockford Fire Department District Chief Will Pederson. The fourth victim was transported to a local hospital, where they died.

Of those injured, one person was in critical condition and four were in stable condition, Rockford police said. The Winnebago County Sheriff’s Office said two more victims were also injured in its jurisdiction, WIFR 23 and The Associated Press reported.

Wednesday's attack came just days after an 18-year-old Walmart employee in Rockford was stabbed and killed. A 28-year-old man was arrested and is facing a first-degree murder charge, according to police.

Police arrested suspect after home invasion report

The suspect was taken into custody by a Winnebago County sheriff’s deputy after they received a report of a home invasion, Sheriff Gary Caruana said.

"The young lady ran from him," Caruana said, describing one of the victims who survived the attack. "She got some stab wounds (in her hands and her face). She is currently at a hospital... in serious condition."

A good Samaritan had stopped to help the woman and suffered some stab wounds, according to Caruana. "He's fine," the sheriff added. "He has been checked out."

Police confirmed that one of the victims killed in the attack was a mail carrier. Rockford Mayor Tom McNamara said multiple jurisdictions are investigating the incident.

"Today, we are shocked by another horrific act of violence against innocent members of our community. We can report that the suspect is in custody and the threat has been neutralized," McNamara said in a statement Wednesday. "Now that he is in custody, our primary concern is ensuring that our community members directly impacted by this violence are supported throughout their healing and recovery."

Jayden Perkins case:Suspect's release before Chicago boy was fatally stabbed leads to prison board resignations

'You never expect this here'

Eric Patterson walked through his neighborhood Wednesday afternoon trying to make sense of a rampage that had turned his quiet street into a crime scene.

Patterson saw two bloody young teenagers and a middle aged woman with a wound to her neck taken by stretcher to ambulances. He saw what appeared to be evidence of a mailman being run over by a vehicle and attacked, his gear left strewn across a yard.

"It makes no sense," Patterson said. "It’s almost like playing a video game, but it's reality. It makes no sense. It’s like Grand Theft Auto. I'm going to run over the mailman here. I'm going to stab a couple people there. I am going to go in this house over here. It’s not making sense. You can’t rationalize this."

Cassandra Hernandez, another neighborhood resident, said she is friends with one of the victims and fears for the life of the mailman who neighbors believe was both hit by a vehicle and stabbed during the attack.

"You never expect this here," Hernandez said. "I just took my dog on a walk right here yesterday morning. ... Just to think that it happened here, and we have such great neighbors and the mailman. I just have a feeling he is gone, and he was a very good man. I am very sad."