On Dec. 11, 1978, serial killer John Wayne Gacy walked into Nisson’s Pharmacy in Des Plaines, Ill., to discuss a remodeling job with the store owner. Little did anyone know at the time that he would meet his latest victim – and the evidence that would help put him behind bars.
It was early evening and Robert Piest, 15, a local high school student and part-time employee, was working alongside his classmate and friend Kim Byers, 17. At one point, Byers borrowed Rob’s parka. During her shift, she filled out a form for developing a roll of film and slipped it into Rob’s coat pocket. Later that evening, Piest would put his jacket back on to take out the trash. Byer’s film confirmation will become an important piece of evidence in the investigation of Gacy, the serial killer who was eventually accused of murdering more than 33 young men, including Piest, his last victim. When questioned by police, Gacy denied ever meeting Piest, but when investigators found the movie receipt at Gacy’s home, they knew he was lying. Now, 46 years after Piest’s death, Byer’s daughter Courtney Lund O’Neil has written a new book Postmortem: What survived the John Wayne Gacy murders about his mother’s friendship with Piesta and how the investigation into his disappearance will lead to his eventual arrest. In an exclusive excerpt shared with PEOPLE, the author recounts her mother’s memories of the last night of Piest’s life.
‘Postmortem: What survived the John Wayne Gacy murders’ by Courtney Lund O’Neil.
Citadel
On December 11, 1978, Kim arrived at Nisson Pharmacy late for her 5 o’clock shift. It was 31 degrees when she arrived. Rob came to work shortly after her, wearing brown pants, a beige shirt, and his favorite blue parka. She worked the cash register, and Rob handled pricing and registering new items for disposal. There was a new person working in the store that night. He was a large man, fat, with slightly relaxed brown hair streaked with silver. The man did not acknowledge Kim. They met in the aisles of the pharmacy. “Who is that guy?” Kim asked the owner, Phil, at the pharmacy counter. “A contractor,” Phil said. “Larry and I asked him to take measurements for the store. You know, a possible facelift.” Phil said it like the performer was a family friend.
Halfway through her shift, a cold hit Kim by the front door. Rob dropped his jacket on top of some boxes by the front left cashier’s counter. “Hey Rob,” she said. “Can I borrow your jacket?” He handed her his blue jacket. In the middle of her shift, Kim decided she wanted to develop a roll of film. She slipped a roll of film into a red and white envelope. Once it was properly filled and sealed, with the film safe inside, she tore off the top receipt. She went to drop the bill in her right hand, but stopped and instead slipped it into Rob’s jacket pocket.
The rest of Kim’s shift dragged on. She wandered around, calling guests and listening to the conversations her boss was having with the strange man in the store. He estimated that the cost of remodeling would be $1,600. The contractor left around 7:15. He also left his coffee-colored booklet on the pharmacy counter.
:max_bytes(150000):strip_icc():focal(749x0:751x2)/John-Wayne-Gacy-Removing-Body-122024-f5980482baa3460f8606ebad2c6f52d8.jpg)
The removal of the body from John Wayne Gacy’s home in December 1978.
Karen Engstrom/Chicago Tribune/TCA
Around 8 pm, it was the end of Rob’s shift and he had to take out the trash. “Hey, can I have my jacket back?” Kim asked. Kim slipped out of her blue jacket and handed it to Rob. He buttoned it up to his chin to keep out the cold. As Rob carried the plastic bags to the dumpster in the back, he noticed school-aged children playing in the snowbanks. The girl noticed him and coquettishly threw a snowball at him. “Hey!” Rob said. The girl laughed and ran down the alley, back to the Iroquois High School dance. In the wind and snow, Rob heaved the trash over his shoulder into the bin [then] headed back inside.
The Night I Was Kidnapped And Raped By John Wayne Gacy — And How I Escaped With My Life (Exclusive)
Sometime in the last hour of Rob’s shift, the contractor returned. He grabbed his forgotten booklet. He paused, noticing Rob. He often hired high school students with good work habits to help him on various projects. It wouldn’t raise suspicion if he offered this kid a job. The contractor meandered; walked erratically through the pharmacy aisles, pretending to look at the shelves again.
At 8:55 p.m [Robert’s mom] Elizabeth Piest entered the store. She greeted Kim, she greeted Rob. The night was supposed to be special. Elizabeth turned 46 and wanted to go back and blow candles. A birthday cake was waiting for her at home. The whole family was waiting for her and Rob in the house. Rob was finishing up the sock business while his mom waited, and he approached Kim for the last time around 9 p.m. “This businessman wants to talk to me about a summer job that will pay me $5 an hour. Do you mind looking ahead a little bit?” The minimum wage was $2.50, so the contractor’s offer made him light up on the possibilities that money could offer. Kim looked at Rob and his image was imprinted in her mind. Loyal, handsome , strong. “See you soon.” He looked at his mother and said, “Okay, honey. I’ll be right back.” ” The door closed behind him and she didn’t think about it. But for the rest of her life she would see him leave, the door closing in slow motion.
:max_bytes(150000):strip_icc():focal(749x0:751x2)/John-Wayne-Gacy-Victim-Funeral-122024-1481015797964b6683be13da1af7de50.jpg)
Robert Piest’s parents, Elizabeth and Harold Piest, attend his funeral on April 18, 1979.
Karen Engstrom/Chicago Tribune/TCA
Rob never returned to Nisson Pharmacy. After about 10 minutes, Kim went to look for him. He disappeared. She saw footprints in the icy snow, tire tracks of the contractor’s car. Rob’s mother also went to look for him and saw nothing. But deep down, a stone immediately formed in the basin of Elizabeth Piest’s stomach. Where could he go? At 21:20 Elizabeth Piest waited more than 20 minutes for Rob to return to the pharmacy. Kim told her that Rob had asked her to watch the cash register outside the store, near the door, while he talked to the construction guy outside.
Never miss a story — subscribe to PEOPLE’s free daily newsletter to stay up-to-date on the best PEOPLE has to offer, from celebrity news to compelling human interest stories.Back home, Elizabeth glanced at her birthday cake, which was hanging on the dining room table in time. “Someone from Nisson’s call?” she asked her husband. Harold shook his head. She grabbed the phone, hoping that Rob had gone back to Nisson Pharmacy and that Kim had forgotten to call. Kim answered the phone. “Not yet,” she said. Mrs. Piest detected concern in the young girl’s voice. “Who was he talking to outside? Who was that man?” The family decided that they would all turn to the police for help.
John Wayne Gacy Survivor Jack Merrill: ‘He Controlled Me One Night But He Didn’t Control My Life’ (Exclusive)
Harold [Rob’s father] drove them to the police station in Des Plaines. The family rushed to the counter to speak with the officer on duty, George Konieczny. Elizabeth breathed in, breathed out, but her fear made it almost impossible to relax. “My son, Robert Jerome Piest, is missing,” she gasped. On December 12, authorities contacted John Gacy. Ronald Adams was the youth worker assigned to the case. Adams called Gacy on the phone and asked him if he had been to the pharmacy the night before. Gacy confirmed that he did. “Did you talk to Roberto Piesta last night?” Gacy was tough. “No, I never spoke to him.” From the book Postmortem: What Survives the John Wayne Gacy Murders by Courtney Lund O’Neil. Reprinted by permission of Kensington Books. Copyright 2025 Postmortem: What Survived the Murders of John Wayne Gacy it is now available at Citadel, wherever books are sold.
Categories: Trends
Source: HIS Education