Updated

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Police in Buffalo Grove, Illinois, believe a husband and father of two is responsible for killing four family members, and then himself, inside their home last week.

Buffalo Grove Police Chief Brian Budds gave the update after all five family members were found dead with "sharp force injuries" in what police had described as a "domestic-related incident."

In the latest update, police said evidence at the scene, information from investigators and the Lake County Corner's examination showed that 39-year-old Andrei Kisliak killed his family.

ILLINOIS POLICE RELEASE NAMES OF 5 FAMILY MEMBERS FOUND DEAD IN HOME, INCLUDES TWO YOUNG CHILDREN

2 children, 3 adults found dead one

Five people were found dead in a home in north suburban Buffalo Grove, Illinois, on Wednesday. (FOX 32 Chicago SkyFOX)

They say he killed his 4-year-old and 6-year-old daughters, Amilia and Vivian Kisliak, as well as his wife, 36-year-old Vera Kisliak, and mother, 67-year-old Lilia Kisliak.

Police said an animal was also found dead inside the home.

Vera Kisliak had sought protection orders in August and September and filed for divorce in July, Fox Chicago reported.  

TWO CHILDREN, 3 ADULTS FOUND DEAD IN AFFLUENT CHICAGO SUBURB HOME

Buffalo Grove home

Buffalo Grove, Illinois, police were dispatched to a single-family residence in the 2800 block of Acacia Terrace for a call of a well-being check on a woman. (FOX 32 Chicago SkyFOX)

A co-worker of Vera Kisliak called the police on Wednesday, Budds said, which led to the discovery of all five family members.

Budds declined to comment on reports from neighbors that the police had been to the Kisliak home in the past month. 

Chicago suburb home where five people were found dead

Five people were found dead in a home in an affluent Chicago suburb Wednesday morning. (FOX 32 Chicago SkyFOX)

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A local resident told the Chicago-Sun-Times she called the police in August over concerns about how Andrei Kisliak treated the children. 

Police said the investigation into the case is still ongoing.

Fox News' Louis Casiano contributed to this report.