Has the Valerie Percy Murder Finally Been Solved?

Two Books Focus on a Suspect Who Once Lived Only a Block Away in Kenilworth






By David A. F. Sweet


Editor’s note: A day before this story was posted, Classic Chicago heard that Valerie Percy’s stepmother, Loraine Guyer Percy, had passed away at 91. Our thoughts and prayers are with the Percys, who have endured too much pain for one family.

Cold cases enjoy a timeless appeal. That’s especially true on the North Shore of Chicago, where unsolved murders are incredibly rare.

The most infamous one garnered national coverage. Valerie Percy, an attractive, friendly Cornell University graduate, lay asleep in the bed of her Kenilworth home one night in September 1966. The daughter of Bell & Howell executive Charles Percy, who was running as a Republican for the U.S. Senate, she had worked hard that summer on her father’s campaign. He called her his best precinct captain.

But that night, the 21-year-old was both beaten and bludgeoned with a bayonet. Her killer bolted after stabbing the victim 14 times; nothing from the Sheridan Road home was stolen. Residents across the North Shore were stunned; W. Clement Stone ordered bulletproof glass installed in his lakefront mansion. Even today, all of us mourn her loss and what the Percys were forced to live through (as a side note, her father was elected Senator for the first time a few months later).


Only 21 years old, Valerie Percy was savagely murdered in Kenilworth in 1966.

Glenn Wall lived only one mile away in Wilmette when Valerie was killed, a 3-year-old who knew nothing about the vicious slaying. But he has authored two well-researched books – Sympathy Vote and Zodiac Maniac – that both make strong cases that an extremely disturbed Kenilworth native murdered Valerie — and got away with it before his own wife murdered him.

Wall’s prime suspect, William Thoresen III, found plenty of trouble in his adolescent years. Born in 1937, here’s a summary, gleaned by Wall from police and newspaper accounts. When he was 13, police warned him to stay away from a Kenilworth family who had complained about him. The following year, Thoreson was caught inside a neighbor’s home more than once without permission. After more troubling behavior, his family placed him in the mental ward at Michael Reese Hospital in Chicago – one of at least three trips to mental hospitals in his life — but he escaped, returned home, locked himself in his room with a gun and said he would kill anyone who entered.

A few years later, he married Louise Banich. Lest one think domestic bliss would change his nature, Thoresen was soon charged with assault of a Kenilworth man.

And that was just in the 1950s. In the next decade, his mother Kay filed assault and battery charges against him. He later tried to stage a murder-suicide in his parents’ home and blame it on his father, also named William, who had founded Great Western Steel in Chicago. As Wall traces in Zodiac Maniac, published last year, Thoresen faced federal charges after an arms raid found 70 tons of munitions in his San Francisco home – including bayonets. (In Zodiac Maniac, Wall makes a persuasive case that Thoresen was also the Zodiac killer who murdered many in California in the 1960s when he lived there.)


Two books have tied one-time Kenilworth resident William Thoresen III to Valerie’s murder.

Fast forward to 1970. One night, his wife Louise claimed Thoresen confessed to three murders, including that of his younger brother Richard, who was killed by a single gunshot to his head in Lake Forest in 1965 (he did not confess to murdering Valerie Percy). Soon after, he said he needed to kill her since she now knew. Instead, Louise shot him dead. A New York Times article a few years later, entitled “Life with a Wealthy, Sadistic, Murderous Lunatic,” cited statements from Louise that he beat her repeatedly, stabbed her and raped her.

That Thoreson was a horrible person is beyond debate. But did he murder Valerie Percy? A World War II bayonet without any rust did wash up on the shore of Lake Michigan a few days after her murder. Three months later, Thoresen’s wife was arrested by the FBI for trying to ship him weapons — including three bayonets identical to the one found near the Percy house. Wall said Valerie’s wounds were consistent with the bayonet, a fact confirmed by her pathologist and by Joe DiLeonardi, a Chicago homicide detective who was dispatched to Kenilworth. Two of the victims of the Zodiac killer were killed with a bayonet and suffered the exact same wounds.

Despite all of this evidence, it seems Thoresen cannot be placed at the scene. At the same time, Wall tears apart theories about other suspects, including a Sun-Times series that won the Pulitzer Prize in the 1970s that claimed a Chicago mobster had killed Percy.

Plenty of bizarre twists mark the Percy case. Though the FBI labeled Thoresen as a suspect after arresting his wife, agents never shared that information with Illinois authorities. Dr. Robert Hohf was called by Percy right after the father found Valerie’s body, and Hohf saw Valerie’s mutilated body moments later, since he lived nearby. Even though Wall pointed out in a newspaper article that investigators said they interviewed about 10,000 people in the first two years of the case, they never interviewed Hohf. 


Author Glenn Wall is unsure why the police reports on the 1966 murder have never been released.

Wall – who originally was going to write a book about Sen. Percy’s campaigns before being drawn into the murder — is stunned that the original Kenilworth police reports on the murder have never been released.

“I’ve seen dozens of cases where original police reports and more have been released in cases this old, including notorious cases,” he said. “I understand the sensitivity of family members regarding crime scene photos, and side with them on that without hesitation, but not old police reports. It’s hard not to think that something’s being hidden.” 

Wall has not spoken with Valerie’s twin sister, Sharon Percy Rockefeller, who conducted her own investigation at one point (those findings have not been made public). Sharon was also home the night her sister was murdered. The Thoresen parents eventually moved to Florida. In their obituaries last century, their son William was not mentioned.

Fifty-four years have passed since Valerie Percy was murdered. With Wall’s books, we seem to be closer than ever to finding the culprit.

Follow David A. F. Sweet on Twitter @davidafsweet. E-mail him at dafsweet@aol.com.