The DuPage County state's attorney says the boyfriend of the couple's daughter hired another man to commit the murders.
Both men are now facing murder and conspiracy charges, although neither of them has a previous violent criminal record.
Prosecutors paint Jacob Nodarse as a triggerman, asked by a friend to kill a family. The alleged mastermind is the ex-boyfriend of the daughter of victims Jeffrey and Lori Kramer. His name is Johnny Borizov, and prosecutors say his plan included giving himself an alibi at the Empress Casino in Joliet, Ill.
"Pursuant to the plan, Johnny Borizov and Nodarse agreed the home would be entered in the early morning hours while Borizov would be seen in the company of another individual and be on tape so he'd have an iron-clad alibi at the time of the murder," said Joe Birkett, DuPage County state's attorney.
Prosecutors say Borizov called Nodarse repeatedly in the month leading up to the murders. The alleged plan included killing Jeffrey and Lori Kramer, along with their son Michael and his sister Angela. Borizov is her ex-boyfriend and the father of her 1-year-old son.
The two had been fighting over custody and faced another court date in the weeks ahead.
"It's alleged that during the course of the murder spree inside the Kramer home, Nodarse looked specifically for Angela but could not find her as she was hiding in a closet, and it was Angela who made the 911 call to police," Birkett said.
ABC7 Chicago news partner, the Daily Herald, reports Jacob Nodarse confessed on a videotape to being the triggerman. Shortly after being arrested at his parent's home in Florida, Nodarse reportedly told police they could find the gun and clothing he wore to commit the crime in a dumspter in Terre Haute, Ind.
Johnny Borizov's attorney says his client is innocent, telling the Daily Herald, "The claims and charges against Johnny are ludicrous and are a figment of the imagination of a mentally unstable person."
Nodarse lived in a Countryside, Ill. apartment owned by Johnny Borizov's uncle. Prosecutors say Johnny's family- who live in Willow Springs - was taking care of his baby when the murdered were committed.
Despite the boldness and brutality of the crime, prosecutors do not alledge Borizov paid Nodarse to commit the killings.
In Darien, the charges bring relief but little comfort.
"I just think about how the daughter must feel to know maybe this was her ex-boyfriend and this is something they'll have ot live with for the rest of their life," said Darien resident Kristy Borse.
"This is a devastating experience. This isn't losing one family member; they've lost three family members. They're devastated," said Birkett.
The two suspects were expected to transported Saturday evening to DuPage County lock-up with a bond hearing expected Sunday. Prosecutors say they will ask the judge to hold the two men through trial without bail. They also say they might seek the death penalty.