On the evening of November 17, 1973, five teenagers from Sioux Falls, South Dakota — Roger Essem (17), Stewart Baade (18), his younger brother Dana Baade (14), Michael Hadrath (15), and Sandra Cheskey (13) — gathered around a campfire at Gitchie Manitou State Preserve in Lyon County, Iowa. Brothers Allen, David, and James Fryer, who had entered the preserve intending to poach deer, encountered the group and, believing they possessed marijuana, decided to rob them by force. Retrieving shotguns from their truck, the brothers opened fire from a ridge, killing Roger Essem instantly and wounding Stewart Baade. After falsely claiming to be narcotics officers, the Fryers separated the survivors: Allen drove away with Cheskey while James and David rounded up and killed Dana Baade, Michael Hadrath, and the wounded Stewart Baade. Cheskey was taken to an abandoned farmhouse near Hartford, South Dakota, where she was raped by James Fryer before Allen drove her home, dropping her off around 5 a.m.
The bodies of Hadrath and the Baade brothers were found along a roadside the next afternoon by visitors to the park; Essem's body was found at the campsite the following day. Investigators initially questioned Cheskey's credibility given her composure and recall of detail, but she passed a polygraph test. On November 29, 1973, while driving the countryside with Sheriff Craig Vinson, Cheskey identified the farmhouse by a distinctive fuel tank, and the pair then happened to see Allen Fryer driving the same truck used in the crimes. He was arrested on the spot, and David and James Fryer were arrested shortly afterward. Cheskey identified David and James Fryer in a police lineup on November 30, 1973. All three brothers were arraigned on December 1, 1973, on four counts of murder, with bond set at $400,000 each.
The brothers were tried separately. David Fryer pleaded guilty on February 12, 1974, to charges including murder and manslaughter and admitted to killing Stewart Baade; he was sentenced to life without parole. Allen Fryer was tried before Judge James P. Kelley in May 1974 and, following testimony from Cheskey, was found guilty on May 20, 1974, of four counts of first-degree murder, receiving four consecutive life terms. After his trial, Allen Fryer and James Fryer escaped from the Lyon County Jail on June 18, 1974, fleeing to Wyoming, where they were involved in a hit-and-run and later arrested after a high-speed chase. James Fryer's trial, moved to Dickinson County, Iowa, concluded on December 20, 1974, with a guilty verdict on three counts of first-degree murder and one count of manslaughter; he was sentenced on January 7, 1975, to three concurrent life sentences plus eight years for manslaughter. All three brothers received sentences of life imprisonment without parole, and their appeals were rejected. In 2016, David Fryer's request to the parole board to allow eventual parole eligibility was denied following testimony from Cheskey and Lynette Hadrath, sister of victim Michael Hadrath. As of 2024, Allen Fryer was incarcerated at the Anamosa State Penitentiary, while David and James Fryer were held at the Fort Dodge Correctional Facility, both in Iowa.