An Illinois couple and three of their children were found brutally murdered inside their home, prompting authorities to warn residents in the farming community Tuesday to lock their doors as investigators work to identify possible suspects.

Authorities discovered the bodies Monday afternoon after responding to a 911 call about possible shots fired at the address, Logan County Sheriff Steven Nichols said at a news conference.

A 3-year-old girl survived the attack and was taken to a hospital in Peoria, he said. The girl's grandmother identified her as the couple's daughter, Tabitha Gee.

Nichols declined to say why his office didn't release information about the slayings until Tuesday morning. He said detectives were trying to identify possible suspects, and that those responsible for the killings should be considered "armed and dangerous."

Nichols warned area residents to lock their doors at night as a precaution.

The slayings, which Nichols described as a "brutal homicide against an entire family," occurred at the family's ranch-style home in Beason, a farming community of a few hundred residents about 140 miles southwest of Chicago.

Nichols declined to provide details about the crime scene or the suspected cause of death, but he said investigators would begin doing autopsies on Tuesday.

Nichols identified the victims and gave their approximate ages: Raymond "Rick" Gee, 46; Ruth Gee, 39; Justina Constant, 16, Dillen Constant, 14; and Austin Gee, 11.

He did not immediately provide details about the girl who survived.

The family was described as quiet and well-liked by townspeople and relatives.

"They were very quiet and very kind and never had a bad word to say about anybody," said Ruth Gee's mother, Francis Constant, who lives in nearby Lincoln.

Raymond Gee hustled for work in construction and as a handyman while his wife, a stay-at-home mom, helped out whenever she could, Constant said.

The couple faced their share of hardships, including having an 11-year-old daughter who suffered a brain injury so severe she has live at a special facility in Peoria. She said her son-in-law also had an adult daughter who did not live at the couple's home.

The couple's children attended church, and waited each morning at the town's post office for the school bus.

In Beason, residents gathered on porches to talk about the killings, some obviously worried about what had happened and the fact that as of late in the day authorities had not made any arrests.

Dale Day, who lives a few blocks from the home where the bodies were found, said Tuesday he'd armed himself to be ready for any trouble that might come his way.

"Now I have my 9 mm loaded, cocked and ready to fire if someone breaks into my house," Day said.

Some residents said they had never considered locking their doors at night.

"Not many people lock their doors here," said Brittney Fillmore, 14, who knew both Justina and Dillen from high school. "Something like this isn't what you'd expect especially happening in a small town where everybody knows each other."

Betty Poston, 76, said she had never seen anything like the shootings since she moved to the town at age 10.

"Everybody always got along, neighbor helped neighbor."

About 70 people crowded into a small Methodist church, where a pastor tried to comfort them, particularly the 30 or so children among them.

"Just think of this family as up in heaven having fun, doing the things that make them happy," the Rev. Dale Badman told those gathered. "They don't want you to be burdened by fear, they don't want you to be burdened by pain."

Robert Bagby, the superintendent of Lincoln Community High School, where Justine Constant was a sophomore, described her as "a very vibrant, likable young lady who had a lot of friends."

Bagby said counselors were at the school for students who needed them.

Two of the children killed, Justina and Austin, attended an area Bible club this summer, said Jordan Peck, who led the club. Both children were attentive and polite, and Justina had become a born-again Christian recently.

Postmaster Jodie Duncan's said the children were never a problem when they waited each morning for the bus.

"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."

The Associated Press contributed to this report.