County coroner Michael Burke identified those killed as: 30-year-old Sara McMeen, 29-year-old Daniel Warren, 8-year-old Skyler Lemke, 7-year-old Ian Lemke and 10-month-old Maggie Warren.
"At 2:36 today on December 16th, 2011 the Livingston County police dispatch received a call of shots fired in Emington, Illinois, which is located in the northeastern portion of Livingston County. Deputies arrived and secured the scene and reported there were five victims," said Martin Meredith, Livingston County Sheriff.
Meredith said McMeen was the mother of all three children, and he described Daniel Warren as her live-in boyfriend. Neighbors say the family had moved to Emington in the last few months.
Authorities found the bodies of a woman, a baby and a young girl in the back yard of a home at 100 block of S. Street. They found the bodies of a man and a young boy in another location nearby.
Emington is a village about 30 miles southwest of Kankakee. The small town was to have a church service Saturday morning as it tries to cope with the shocking deaths.
The boy was in kindergarten, the girl in second grade and the baby less than a year old. All were apparently members of the one family and victims of an apparent murder
Investigators announced the latest on the case at a news conference Saturday morning.
"As your sheriff of Livingston County, I want to make everyone understands that you are safe and that the deputies are on the road, and we are looking for no persons of interest at this time," said Meredith.
The town, with just 120 residents, includes a volunteer fire department which had the difficult job of responding to the scene and finding the bodies of friends and neighbors.
"Like any small town, nothing like this has ever happened. We're all in a state of shock," said Bob Young, Livingston County Board member.
The Associated Press contributed to this report