The Ripper Crew:

(Warning for content) 

The “Chicago rippers” or as they are more commonly known, “The ripper crew”, were a self-proclaimed Satanic group, which included a member named Robin Geght, who was a previous employee of clown killer John Wayne Gacy. 

Along with two brothers, Andrew and Thomas Kokoraleis and their associate Edward Spreitzer, the Ripper crew allegedly cruised around in their van, preying on unsuspecting woman who were often, but not always, working as prostitutes. 

They hunted these women in order to sacrifice them in a ritual that would involve cutting off, masturbating on and consuming their breasts, while reading verses from Anton Levay’s Satanic bible out loud. They were also said to have raped the wound, and were thought to have murdered 18+ victims. The group was eventually caught, when a victim, Beverly Washington, managed to survive an attack. 

Although raped and having had her breast severed, as with the other victims, she managed to hold on and was found alive by some rail road tracks. She gave a description of both the men and their vehicle, leading to their conviction. 

They confessed, and despite Geght claiming his innocence, he got 120 years. Thomas Kokoraleis was sentenced to life, having confessed to his crimes, and is due to be released from the Illinois River Correctional Center where he is currently incarcerated on September 30th, 2017. 

His brother Andrew was executed. 

He was last inmate to be executed in the state Illinois.

Sources: https://en.wikipedia.org/wiki/Ripper_Crew
http://www.viralnova.com/ripper-crew/
http://murderpedia.org/male.G/g/gecht-robin.htm