UPDATED: 6/10/2011 2:20 p.m.

VERNON HILLS, Ill. (CBS) — The husband of a Vernon Hills woman who was found dead in her home earlier this week has now been charged with her murder.

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Lake County prosecutors say a “lack of sleep” is the reason the man allegedly killed his wife on Wednesday.

As WBBM Newsradio 780’s Mary Frances Bragiel reports, the body of Rachel Stolberg, 54, was found in her home in the 300 block of Farmington Lane in Vernon Hills. Her husband, Ronald Stolberg, 47. called police at 5:21 p.m. that day and said he had found her dead.

But police now believe Stolberg was responsible for her death. Detectives determined in interviews that there had been a domestic struggle in the house in the hours before Ronald Stolberg called police.

Stolberg first told investigators that he completed his shift at a Buffalo Grove electronics manufacturer and came home to find his wife Rachel dead.

Prosecutors say after the Lake County Major Crimes Task force got involved they discovered that Stolberg killed his wife as the two argued because she kept waking him up during the night.

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LISTEN: Newsradio 780’s Mary Frances Bragiel reports

Meanwhile, Naperville police are searching for the brother of Cathleen Lewis, who was found dead in her home after being hit in the head earlier this week.

Lewis, 59, was found beaten to death Wednesday night in her condo in the 2300 block of Worthing Drive, police said. Her body was found during a well-being check.

Police are now looking for her brother, Mark Lewis. Naperville police Sgt. Gregg Bell tells the Daily Herald that Mark Lewis is not considered a suspect, but police are concerned because no one has heard from him in a few days.

Detectives say there was no forced entry into Lewis’ home, and believe she knew her killer.

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The Sun-Times Media Wire contributed to this report.