Kathleen Hazel Pehringer, 41, disappeared from her home on 1st Street in Riverton, Wyoming, on April 17, 1989. Pehringer lived with her 14-year-old daughter in a one-story white house with black trim across the street from Ash Grove Elementary School. That afternoon, Pehringer's daughter returned home from school to find her mother gone; Pehringer's car remained parked in front of the house, and there was no note explaining her absence, which was uncharacteristic of her. There were no signs of a struggle. An ashtray that was normally full had been emptied except for two cigarette butts, one matching Pehringer's brand and one her daughter attributed to an acquaintance of Pehringer's, Donald Kenneth Pack Jr. That same afternoon, Pack came to the house looking for Pehringer, asked to use the phone, dialed a number, hung up without speaking, and left. Pehringer had taken her purse and eyeglasses with her. At the time, she was taking classes at Central Wyoming College and working part-time at the Hilltop Bar in Riverton. She has not been seen or heard from since.
The Riverton Police Department investigated the disappearance and later transferred the case to the Wyoming Division of Criminal Investigation (DCI) cold case unit in 2012. Pehringer was declared legally deceased in May 1998, and the case is classified as a homicide investigation. Pack, who knew Pehringer through her ex-boyfriend, was not charged in connection with her disappearance and has denied any involvement; DCI has described him as a subject of investigative interest but has not formally named a person of interest as of April 2024. Pack was later convicted in 2018 of two 1970s rapes in Teton County after DNA evidence was developed during a review connected to Pehringer's case; he served additional prison time and is on parole through January 2027. The case remains open. Identifiers: NamUs #MP11958; Doe Network #1000DFWY. Anyone with information is asked to contact the Riverton Police Department at 307-856-4891, the Fremont County Sheriff's Office at 307-332-1000, or the Wyoming DCI at 307-777-7181. Case Number 2012-0271/R10-08888.