Initial searches

Eggleston's absence was first noted when she failed to return to Allnet's Lake Oswego office, where she was supposed to meet her advisor at 5:00 p.m.^[9] At around 5:00 p.m., a witness named John Davis^[14] sighted Eggleston's grey Volkswagen Golf still in the Port of Portland Building parking lot.^[9] When Eggleston failed to return to the home she shared with her sister Janet, Janet notified their father, who traveled to the Portland area from Redmond on August 3.^[9]

In the early morning hours of August 3, a security guard at an industrial complex located at Northeast 122nd Avenue and Airport Way discovered Eggleston's Volkswagen Golf parked in the lot, approximately 9 miles (14 km) from the Port of Portland Building where it was last seen, near the Portland International Airport.^[9] The doors to the car were unlocked, and all of its windows were rolled down, with the keys still in the ignition.^[11] Her purse and its contents were in the car, including a checkbook, credit cards, and a small amount of cash,^[15] though her passport was absent.^[16] Eggleston's parents noted that she had retrieved her passport from their residence in Redmond while visiting 10 days prior.^[17] On August 6, fields located nearby were searched by volunteer searchers, as well as other underbrush, gravel roads, and farmlands.^[8] Eggleston's employer, Allnet, paid for additional air searches, which were followed with ground searches using bloodhounds.^[8] On August 6, Portland Police spokesperson Derrick Foxworth told reporters that "it certainly looks like we might have a homicide."^[15]

Theories

Eggleston's parents initially suspected her then-boyfriend, a Redmond resident, of her disappearance, but he was cleared by law enforcement who confirmed he had been in central Oregon at the time she disappeared.^[12] Though initially suspected as a homicide, the Portland Police Bureau subsequently theorized that Eggleston had gone missing intentionally,^[14] possibly to avoid testifying in a potential court case against her sister, Janet, for tax evasion.^[14] Janet and her former husband were accused of failing to report around $190,000 in business income between 1986 and 1987.^[17] This revelation, and detectives' focusing on it as a potential motive for Eggleston to flee, led to strife between the family and investigators, specifically lead detective Terry Wagner.^[12] Paul Eggleston later stated: "Wagner made it crystal clear she was not going to talk with us, that she still believed Katie probably disappeared of her own will."^[12]

Eggleston's family subsequently hired a retired Oregon State Police detective to further investigate the disappearance case, and several leads were produced; one of the leads regarded a security guard who possessed keys to the Port of Portland Building's parking garage.^[14] To further search efforts, Allnet funded a tip hotline dedicated to tips in Eggleston's disappearance,^[18] while fliers promising a $5,000 reward were distributed along Interstate 5 between Eugene and Everett, Washington in mid-August.^[18] One anonymous call placed to the tip hotline was made by a man who claimed to have abducted Eggleston and murdered her two weeks after her disappearance.^[14] The anonymous caller, who allegedly spoke with a Southern dialect, stated that she would never be found "because I killed her."^[12]

By October 1993, police had received hundreds of tips in the case, but none proved fruitful.^[17] On October 12, law enforcement told the media that they maintained their stance that Eggleston had disappeared willingly, citing the lack of physical evidence, as well as Eggleston's missing passport, again suggesting she had fled to avoid testifying against her sister Janet.^[14] However, Janet and her ex-husband, Jeffrey Taylor, had both pleaded guilty to their charges on July 9, forgoing a trial, meaning Eggleston would not have had to testify in the first place.^[17] After her October 12 sentencing over the tax evasion charges, Janet told the media that her case was unrelated to her sister's disappearance, commenting: "To imply any connection tarnishes her in a way that is unbelievably painful to me."^[17] Eggleston's father Paul commented in letter correspondences to investigators: "Katie may be a government witness, but her contribution to the case has to be minimal. She doesn't know any more than Sarah (her younger sister, also a potential witness) about Jeff's finances."^[12]

Subsequent developments

On May 4, 2001—Eggleston's 30th birthday—her family set up a hotline seeking additional tips in her disappearance.^[12] One man who called was a former attendant at a gasoline station located at Northeast 122nd Avenue and Stark Street, who claimed to have seen Eggleston near the time she disappeared.^[12] This gas station is located approximately 4 miles (6.4 km) south of where Eggleston's vehicle was discovered.^[12] The attendant claimed to have given a woman he believed to be Eggleston directions to the airport.^[12] According to the attendant, she departed in a vehicle whose make and model he could not recall.^[12] A short time later, the woman returned to the gas station, this time in a different car—a blue-green Honda hatchback—and accompanied by two black men.^[12] According to the attendant, the woman appeared "disheveled, partially undressed and crying," and seemed to be doing things to attract attention, such as driving erratically.^[12] The attendant also noted that, when the woman had first arrived alone, he noticed a "thick, black book on the passenger seat" of her car, resembling the salesbinders used by Allnet.^[12]

Law enforcement's stance that Eggleston willingly disappeared was maintained until the 2004 disappearance and murder of Brooke Wilberger in Corvallis.^[19] Wilberger's murderer, Joel Courtney, was allegedly in Portland at the time of Eggleston's disappearance, and is considered a possible suspect.^[20] In 2006, the Federal Bureau of Investigation announced that Courtney had been cleared in two unnamed disappearances, though Eggleston's father told The Oregonian he had been informed that Courtney was still being examined as a potential suspect in her case.^[21]

Eggleston's mother, Heather, died in July 2011,^[5] followed by her father Paul, in March 2017.^[4] Both of Eggleston's parents consistently maintained that their daughter had been murdered.^[12] As of 2023, her whereabouts remain unknown.