The victims are Raymond Gee, 46, and Ruth Gee, 39 and their three children- Justina Constant, 16; Dillen Constant, 14; and Austin Gee, 11. All five were shot to death, police said, and their bodies were found Monday after someone called 911 to report a possible shooting. One child - a 3-year-old girl - was airlifted to a Peoria hospital. Her condition is unknown
"This was a brutal homicide against an entire family. And we are determined to identify and arrest those responsible," said Logan County Sheriff Steve Nichols.
Sheriff Nichols said the suspect- who has not been identified- is considered armed and dangerous. Nichols urged residents to lock their doors and remain cautious until the killer is caught.
Autopsies were being conducted Tuesday.
Beason is a farming community about 140 miles southwest of Chicago.
The Glee family was quiet and well-liked, according to others in the tiny community. The post master said she saw the children every morning when they came to catch the bus for school.
"They were great kids," she said. "Austin was in the post office every morning in the lobby on the floor doing his homework. He'd say he's more awake in the morning."
She said Raymond Gee worked in construction and that Ruth Gee was a stay-at-home mother.
The Associated Press contributed to this report.