Three other people inside the house survived.
Jeff Kramer, 50, his wife, Lori, 48, and their son, Michael, 20, were shot to death early Tuesday morning. Police were called to their home at 8904 Kilkenny Drive in Darien, Ill., by their daughter, Angela.
Angela, 25, and another brother, Anthony, 29, escaped, as did Michael's 17-year-old girlfriend.
Forensic investigators returned to the home Tuesday night searching for any bit of evidence they might have overlooked earlier. The bodies of the couple and their youngest son were all found on the main floor of the house. The front window was broken, apparently by the gunman as he entered or left the house. Police say they are confident it was someone who knows the family, not a random gunman.
"I have been a policeman 32 years and my experience is that this is not a random act. At 3 o'clock in the morning on this particular street, someone didn't just walk up and decide to start shooting inside of a house," said Chief Robert Pavelchik, Darien police.
"It certainly rests easier with the neighborhood to know that it was something targeted rather than random. But that said, it's horrible," said Bill Kohlsat, neighbor.
The Kramers' daughter, Angela, called 911 as she hid in a closet inside the house. Their son, Anthony, and Michael's girlfriend were also in the home and heard the shots but managed to escape.
Friends left wreaths in the family's front yard Tuesday night. They recall backyard football parties and other get-togethers there.
"Fantastic family. You couldn't ask for better friends," said Donna Hovorka, Kramer Family friend.Jeff owned a towing company where he was considered a workaholic but also a generous boss. Jeff Kramer owned a Cicero towing company where he was regarded a workaholic but also a generous boss.
"I really don't think I've ever seen him say no to anybody. It's just hard to believe," said Jim Roth who worked with Kramer.
Police have interviewed the three survivors and consider none of them a suspect and they say none of apparently caught a glimpse of the gunman either.
"Anytime a horrific crime like this occurs in your community you are frustrated and aggravated. This kind of thing shouldn't happen to anyone and we're going to put the available resources that we have to come to a conclusion to this," said Pavelchik.
The coroner is planning autopsies on the victims' bodies Wednesday, which should help determine what kind of gun was used and how many shots were fired. At this point, they have not recovered a weapon.