David Meirhofer was born on June 8, 1949, in Bozeman, Montana, to Clifford and Eleanor Meirhofer, and he was one of their five children. Shortly after his birth, the family relocated to Manhattan, a small town where David grew up. He attended Manhattan High School and was often perceived as an outsider due to his melancholic and introverted nature, leading to periodic bullying from peers.

After graduating in 1967, Meirhofer took on various odd jobs until he was drafted into the Army in the fall of 1968. He then enlisted in the Marine Corps on October 1, and spent the next few months at a military base in San Diego, California, as part of the Signal Corps. Following his basic training, he was stationed at MCAS Cherry Point before being deployed to Vietnam in 1969, serving in the 5th Communications Battalion. For his contributions to communication systems and military operations, he received the National Defense Service Medal, the Vietnam Service Medal, and the Vietnam Campaign Medal. He returned to the U.S. in August 1971 and continued his service at Marine Corps Base Camp Pendleton.

In 1973, Meirhofer was honorably discharged from the Marine Corps and returned to Manhattan. He made a living as a self-employed handyman and carpenter, operating a shop in the town.

David Meirhofer first drew police attention with the kidnapping of 7-year-old Susan Jaeger. She was taken from a tent during a family camping trip at Missouri Headwaters State Park on June 25, 1973. Three days later, an anonymous man called an FBI office in Denver, Colorado, claiming to have abducted Susan and demanded $25,000 ransom. On July 2, a similar call was made to Deputy Ron Brown of Gallatin County Sheriff's office, this time asking for $50,000. The caller provided details about Susan, including a distinctive feature on her fingernail, which her family confirmed. Although police planned to catch the kidnapper during the ransom exchange, no one showed up at the drop-off location.

On September 24, the kidnapper called the Jaeger household, speaking to Susan's older brother, Daniel, and referenced previous calls to the sheriff and FBI to establish his identity. The call was recorded, leading the FBI to trace it to a gas station in Cheyenne, Wyoming. However, they could not apprehend a suspect, and the case went cold.

In February 1974, about 1,200 skeletal fragments were discovered at an abandoned ranch in Three Forks, Montana. Forensic analysis revealed the remains were of a girl aged 6-8 and a woman aged 18-20. On June 25, the kidnapper contacted the Jaegers again, talking to Susan's mother, Marietta, and confirmed his identity by describing Susan and previous calls. A Three Forks resident, Ralph Green, reported an unknown call on his phone bill, which led police to find tampered telephone cables. This led FBI profilers to create a psychological profile of the suspect, suggesting he was a local white male in his mid-20s to early 30s, likely with a background in telecommunications or the military.

Investigators eventually focused on David Meirhofer, who matched the profile and had been seen frequently in Three Forks. His travel records placed him in Wyoming on the day the Jaegers received the call. Meirhofer was arrested in August 1974 but denied involvement, even under the influence of sodium pentathol and a polygraph test, which were inconclusive. Without solid evidence, he was released.

Susan's parents identified Meirhofer's voice from recordings of the ransom calls. On September 24, Meirhofer, using the alias "Travis," called the Jaegers again, threatening they would never see Susan alive due to police involvement. The FBI, monitoring the call, confirmed his identity and arrested him the next day.

While in custody, searches of Meirhofer's home and car revealed bloodied women's clothing and human remains. Confronted with this evidence, Meirhofer confessed to killing Susan Jaeger and 19-year-old Sandra Dykman Smallegan, whom he had kidnapped and accidentally killed. He also admitted to dismembering their bodies and disposing of them at the Lockhart Place.

To avoid the death penalty, Meirhofer confessed to two additional murders: 13-year-old Bernard Poelman in 1967 and 12-year-old Michael Raney in 1968. Despite suspicions of more victims, he only admitted to these crimes due to a plea deal. Meirhofer committed suicide in his jail cell shortly after confessing, ending his brief but violent criminal spree.

David Meirhofer's motives remain unclear, and some of his suspected crimes were later attributed to other perpetrators. His younger brother, Alan Meihofer, was convicted of unrelated child rapes in 1988 and released in 2017. Alan has refused to discuss any potential connections between his and David's crimes.