Here's some info. Some is not on web anymore but I have it in print.
Here's a forum on the WHOLE CASE:
http://p216.ezboard.com/fcrimeandjustice13552frm92
http://weeklywire.com/ww/11-02-98/chicago_cover.html
HERE'S A BRIEF ARTICLE NO LONGER AVAILABLE. AUTHORSHIP UNKNOWN
An intruder entered the home of Senator Charles Percy (Rep.-IL) in Kenilworth, Illinois, on September 18, 1966, and brutally murdered his 21-year-old daughter, Valerie Percy. Senator Percy, a Christian Scientist, was the former President of Bell and Howell. Valerie Percy died of a fractured skull and 14 stab wounds: "An autopsy today showed that two stab wounds in the abdomen had penetrated the liver, one in the left breast had penetrated the heart, one in the right breast had reached a lung, and one through the throat had been stopped by the spinal column. Coroner Andrew J. Toman said there were also several cuts on the face, apparently inflicted with a double-edged knife, and several abrasions, like tooth marks, on two fingers of her right hand. But he said that death was caused by heavy blows to the left side of Miss Percy's head. He said the blows had probably been inflicted before the knifing since the victim did not scream. He said they had shattered her skull, leaving triangular depressions." [NYT 9.20.66 p43] Cash plainly visible on the dresser was left undisturbed. This was the first murder in Kenilworth in 75 years. Senator Percy's wife heard moaning from Valerie Percy's bedroom and discovered her murderer standing over her with a knife. The murderer had found his way onto the back patio of the Percy's home and cut through the locked screen door and pane of glass to gain entrance. The police conducted an extensive investigation and theorized the murderer was familiar with the layout of the Percy estate because the family dog alerted no one to the intrusion. The crime remained unsolved. When Charles Percy commenced his Senate campaign against Senator Paul Douglas (Dem.-IL), the police advised him to hire a bodyguard because he may have been the intended victim of the killer. Senator Paul Douglas, a former Marine, campaigned as a hawk, and suggested that small nuclear weapons should be used in Vietnam. Charles Percy wanted an Asian peace conference.
Former Vice President RICHARD NIXON was scheduled to campaign for Senator Percy around this time. He canceled his plans to do so and attended Valerie Percy's funeral. Senator Charles Percy was on NIXON'S Enemies List in the early 1970's. In 1971 Senator Charles Percy was also the victim of a bugging device; it was positioned on the underside of his car. On June 21, 1972, the FBI reported on a telephone number connected with the Watergate break-in this manner: "Telephone number three one two dash W T E A U E O T is believed to be typing error created by misplacing of hands on bottom line of keyboard. Instead of third, above letter combination would result from an intention to strike number two five three dash seven three nine five." (Striking of letter "A" was unexplained.) This telephone number lists to Thomas J. Houser. Chicago indices reflect Thomas J. Houser was formerly state campaign manager for U.S. Senator Charles H. Percy, in 1966...Was counter-intelligence agent U.S. Army...Thomas J. Houser will be contacted regarding his knowledge of McCORD and other Subjects..." [WFO 139-166 6.2172 rec. 6.27.72 serial illegible 139-4081-76]