Police in Joliet said Romeo Nance was found by US Marshals near Natalia, and the 23-year-old took his own life after a confrontation.

Investigators have said they did not know of a motive for the killings, but said the man knew the victims.

The victims were found on Sunday and Monday at three separate locations - several hours after the authorities warned on social media that the man should be considered "armed and dangerous".

One of the people killed was found on Sunday in a home in Will County. Seven others were found on Monday at two homes in Joliet.

Authorities said they also believe another shooting in Joliet that wounded a man on Sunday is connected to the string of violence.

Joliet Police Chief William Evans said: "I've been a policeman 29 years and this is probably the worst crime scene I've ever been associated with."

Will County Chief Deputy Dan Jungles he did not know how long the people in the houses had been dead.

Evans said the victims found Monday in the houses were members of the same family.