The bodies were discovered in a home just one block from a house where a couple and their son were killed in 2010.
The crime scene is located in unincorporated DuPage County near Darien.
Police began arriving to a neighborhood in unincorporated Downers Grove in the afternoon for a reported disturbance.
Some neighbors say they were told to take cover in a basement because there had been a shooting incident.
Information began to trickle out. There were multiple victims at a residence on Oldfield.
The investigation happens to be a block away from another tragedy. In 2010, Jeffrey, Lori and their adult son Michael were killed.
Two men, Johnny Borizov and Jacob Nodarse, have been convicted for the Kramer family murders and await sentencing.
Neighbors are protective of the surviving Kramer family who still live in the neighborhood.
Police say it appears this was an isolated incident and no one in the community is in danger.