Funeral services were held Thursday for four victims in the murder-suicide in Emington, a small farming community about 80 miles southwest of Chicago.
A funeral for Daniel Warren, 29, and his daughter, Maggie Warren, 10 months, was held at the Fruland Funeral Home in Morris.
"[Maggie] was a sweet innocent angel," said Lisa Nelson, a family friend. "She was a beautiful little baby girl."
Nelson said Daniel Warren was an "awesome young man" and called him a "good dad with a very kind soul."
Services for Skyler Lemke, 8, and Ian Lemke, 7, were at Emmanuel Lutheran Church in Dwight.
Police say all four were shot by Sara McMeen, 30, before she took her own life last Friday afternoon.
McMeen, who is said to suffer from bipolar disorder and postpartum depression, was mother to the three children. Daniel Warren was her live-in boyfriend. His mother, Wendy, told NBCChicago, "It doesn't make sense, and I'll never be able to understand it or put the pieces together."
McMeen was buried Wednesday. About 125 people attended.
"The McMeen family are very faithful in their desire to love the Lord, and I'm just here to kind of support them in their loss," said Pastor Roy Leve, a family friend, who attended her funeral.
McMeen apparently suffered from bi-polar disorder and postpartum depression.
According to court records, McMeen's father fatally shot his first wife about 10 years before McMeen was born. The shooting happened in front of the couple's 2-year-old son.
At the time, Louis McMeen, who was then 20 years old, told police that he and Pamela Bradley McMeen, also 20, had gotten into an argument in his car on Jan. 25, 1971, and that she got out and said she was walking home.
"This is where I think I might have gone black,'' he reportedly told Livingston County prosecutors back then.
He said the next thing he remembers is picking his son up off the ground before putting his wife's bleeding body in the car. She had been shot with a 12-gauge shotgun.
He then drove to a police station in nearby Streator and told officers, "I just murdered my wife,'' according to the police reports.
A jury found Louis McMeen not guilty by reason of insanity. According to records, he had been released from a psychiatric hospital about a month before the killing, after suffering what his doctors diagnosed as "an acute schizophrenic episode.''
Sheriff's officials have said they may never know Sara McMeen's state of mind before last week's killings involving her family. They were waiting until after the funeral services this week to interview relatives.