Mary Kay Heese, a 17‑year‑old high school junior from Wahoo, Nebraska, never made it home after school on March 25, 1969. Her disappearance sparked a townwide search. Near midnight a farmer found her schoolbooks and purse stacked by a rural road; not far away, her body lay in a ditch. Investigators determined she had been beaten and stabbed 14 times. Her shoes, tire tracks and a castable shoeprint were documented; no knife was recovered.
The slaying broke the rural community’s sense of safety. Mary Kay’s family described her as shy, eager to fit in—practicing twirling and hoping to find a date for a school dance. Early witness reports placed her getting into a two‑man car at a street corner soon after school. Police polygraphed many local men and questioned dozens, but follow‑up work in 1969 was uneven: cars weren’t always checked for blood, suspects’ shoes weren’t compared to the track casts, and there was no DNA testing in that era.
Two names surfaced repeatedly in the original files: Joseph Ambroz and Wayne Greaser. Ambroz, 22 at the time, was new to town, had been on parole for earlier offenses and worked on a slaughterhouse “kill floor.” People remembered him talking with Mary Kay around town; others said he expressed sexual interest in her. Greaser and Ambroz were said to be each other’s alibis.
The case stalled and eventually cooled. For decades it remained unsolved. In 1999 the Nebraska State Patrol established a Cold Case Unit. Sergeant Bob Frank re‑examined the reports and evidence as forensic methods had advanced. He reinterviewed witnesses, re‑tested clothing and books for prints and DNA, and traveled to question Ambroz in Florida. Ambroz denied involvement; his DNA did not match material tested on Mary Kay’s possessions, and polygraph results were inconclusive. Investigators described many interviews as hearsay. Frank ultimately presented what he’d gathered to prosecutors, but at the time there was insufficient evidence to move forward.
The case lay mostly dormant until 2015, when Saunders County investigator Ted Green began piecing together decades of scattered reports, memos and witness statements. Green re‑interviewed people who’d been in town in 1969 and pursued previously overlooked leads: accounts that Ambroz had talked about Mary Kay, seen her around town and even said he “wanted to do her”; reports that Ambroz and Greaser had argued the night of her disappearance; and a co‑worker’s claim that Ambroz had boasted “I can do six months, but I can’t do life,” suggesting motive tied to parole risk.
A crucial public tip arrived in 2019 via a Facebook page set up by a friend of the family. The tipster recalled rumors that a car like Ambroz’s—described as a two‑tone ’56 Chevy—had been dismantled and pushed into a local reservoir shortly after the murder. Green followed the tip and, with civilian dive team Adventures with Purpose, began recovery efforts in the reservoir that produced metal fragments and fiber consistent with a car interior. Those finds couldn’t conclusively prove the car’s identity without draining the reservoir, which was infeasible.
Green then pursued forensic avenues back on land. In 2024 authorities obtained permission to exhume Mary Kay’s body for a second autopsy. Remarkably well preserved after 55 years, her remains were re‑examined by a pathologist. Investigators say the wound patterns were consistent with methods taught to slaughterhouse workers—how to sever or stab in a way used in animal processing—matching the kind of knives and techniques Ambroz would have known from his kill‑floor job. That finding joined other circumstantial elements: a shoeprint at the scene matched a size that Ambroz wore and its tread was similar to prison‑issue footwear he could have been wearing at the time; witness statements placed Ambroz and Greaser in the area; and several witnesses reported things they said the men had told them about the night.
In 2021 Green interviewed Ambroz, who by then was living elsewhere and appeared frail. Ambroz told Green his car had blood on the left rear fender the night of the homicide and claimed it was from hitting an animal; Green believed the blood was Mary Kay’s, possibly from her being pinned on the trunk. Green compiled the witness statements, the shoe and autopsy evidence, the reservoir tip and other investigative work and presented it to the Saunders County attorney.
A grand jury indicted Joseph Ambroz on first‑degree murder charges. Prosecutors said the case would be difficult at trial—no murder weapon and no DNA tying Ambroz directly to Mary Kay—but they believed the accumulated evidence and witnesses were sufficient to proceed. Ambroz, then in his late 70s, was arrested on November 18, 2024, in Oklahoma and extradited to Nebraska.
Months later, rather than a first‑degree murder conviction, prosecutors and defense reached a plea deal. In July 2025 Ambroz pleaded no contest to conspiracy to commit first‑degree murder; the plea named the deceased Wayne Greaser as co‑conspirator. No contest pleas do not include an admission of facts, and Ambroz did not provide details about the homicide. The deal and plea prompted anger and heartbreak among Mary Kay’s relatives and investigators. Saunders County officials said they took the agreement because of evidentiary challenges, witness attrition over more than five decades and the difficulty of securing a conviction beyond a reasonable doubt at trial.
Because the crime occurred in 1969, sentencing had to follow the statutes in place then. The maximum penalty for conspiracy to commit murder in 1969 was two years; with Nebraska’s good‑time rules, Ambroz’s sentence was reduced, and with credit for time served he was released in November 2025. Ambroz’s attorney said his client maintained his innocence and accepted the plea because of his age and health.
For Mary Kay’s family and the Wahoo community, an arrest and a legal resolution did not erase decades of questions. Investigators said the case showed how forensic advances, persistent re‑investigation and a community tip combined to move a half‑century‑old case forward. Family members sought answers throughout, asked investigators to keep working and held out hope for a fuller accounting that the plea did not deliver. The case remains a reminder of both the limits and the possibilities of cold‑case work: new science and dogged detective work can yield leads and charges after many years, but lost witnesses, faded evidence and legal limits tied to when a crime was committed can constrain the pursuit of the full truth.