Police were called to the home at 194th and York Drive in Mokena just before 8 p.m. Friday. There they found the body of Sabrina Clement in the basement.
That particular block York Drive was quiet Saturday as residents struggled to understand what happened hours earlier. Police say 18-year-old Randulich stabbed his 4-year-old half-sister to death.
"He's a really quiet kid. His whole family didn't talk much to anyone, just kept to themselves," said neighbor Matt Wisch.
Investigators say it is possible the Randulich made the 9-1-1 call bringing officers to the home where neighbors say the family had lived for less than one year.
"About 7 or 8 o'clock, the cops came flying by. about 15 minutes later, they brought the kid out with blood all over his pants and shirt," said Kenneth Oehemke, who lives in the area.
The body of 4-year-old Sabrina Clement was found by police in the basement on the floor of the recreation room. She was pronounced dead at the scene. Saturday afternoon, the Will County coroner's office says their preliminary examination shows the girl died from a sharp force injury to the neck. Investigators would not identify the object used in the attack.
"It was pretty quiet at the house. The two boys were there, and we located the victim and the two individuals were detained," said Commander Dan Rankovich of the Mokena Police Department.
Police say, at the time of the incident, Randulich was home alone with his 16-year-old brother, who was unharmed, and his half-sister. Randulich and the victim have the same mother. The children's parents were out for the evening.
"I just hear her crying and screaming, 'What do you mean my baby girl?' Why can't I go in the house?' They were holding her back," said a neighbor who identified herself as Gina.
Randulich has been charged with first degree murder. Detectives say he has been cooperative, but they offer no motive as to why the teen, who was suppose to graduate from high school next week, allegedly killed his little sister.
Police have not whether or noth Randulich's 16-year-old brother will be charged. An autopsy for the victim was set for Sunday.