Lizzie did know who the killer was, so did Emma and their uncle.
In fact the only person in that house who did not know the killer was Bridget, she is the saddest character of the entire affair. After the trial Bridget would leave the Bordan employee and move to Colorado where she worked as a cook on a cattle ranch. She died in extreme poverty in (I believe 1918) and was buried in a paupers grave.
Let us dissect the murders:
1) Mrs. Abby Bordan was a hymopheliac (one whose blood cannot clot), the first blow to her skull would have been enough to kill her outright. The additional blows were pure rage;
2) Mr. Andrew Bordan was a tight fisted rude and obnoxious man who loved no one;
3) Mr. Bordan arrived home at about 12:00pm, his usual time in order to have lunch. The front door was locked and Bridgett had a time getting the door open. It was at this time she heard a laugh coming from the up[stairs, she thought it was Lizzie;
4) By 12 noon Abby lay dead upstairs and because Bridgett theough she was out, she did not look into the guest room, had she she would have found Abby dead;
5) Andrew took off his boots and overcoat, folded the coat and ulaid it on the arm of the couch (see photo);
6) shortly after Andrew fell asleep the killer went downstairs from where he had hidden in Emma's room, and confronted Andrew by shouting out "Father" or more than likely "You old b*a*s*t*a*r*d.";
7) Andrew wakes up and finds the killer standing over him;
8) Andrew puts on one of his boots and starts to put on the other when the killer strikes (look at the crime photo, AB has one shoe on his right foot and the left foot is part way into the other shoe). He was sitting up at the time he was struck.
The killer struck each victim with nothing but pure rage coursing through his veins. He had been denied his inheritance, a portion of Andrew Bordan's estate, which by law should have been his as the eldest child of Andrew Bordan!! Michael William Bordan was the only child of Andrew Bordan's first wife. AB being the *A*H that he was had his wife commited to an insane asylum after their son turned 8, sent the son off to another family and had the marriage invalidated, based on his wifes being institutionalized, and his son declared a b*a*s*t*a*r*d.
It takes one to know oneWilliam Bordan became a pig farmer in upstate Massachusetts and never married (wonder why?). The brother of Andrews second wife, the mother of Emma and Lizzie, found out about Michael and attempted to get Michael even a portion of the money due him, it almost worked.
Lizzie had unlocked the cellar window to allow William into the house by her uncle's instructions. Emma knew about the confrintation arranged by their uncle and stayed away for her own safety. Had she stayed she too may have been killed.
After the killings William left through the backdoor and over the the back fence.
The blood splatter? Isn't any to speak of is there? William knew how to slaughter hogs with no blood splatter. Only minute specks of blood are on the walls above Abby's head and a mere dozen are on the wall above Andrew's body and the police did not fine them until the third day because the wallpaper had small red flowers on it.
Any questions students?