Rookie Detective’s Persistence Leads to Life Sentence in Husband’s Insulin Death

Skyler Rocz had been a sworn detective for barely six weeks when a deputy’s January phone call sent her to a Texas hospital for what she later called a “once-in-a-lifetime case.” That initial call launched an investigation that grew far beyond a single suspicious hospital admission and ultimately produced a murder conviction.

From Hospital Callout to Murder Indictment

On Jan. 7, 2023, Joseph Hartsfield, 46, was admitted to a hospital east of Houston unresponsive after a severe blood-sugar crash. Although he was diabetic, he did not respond to treatment. Hospital staff suspected an excess of insulin. The Harris County Institute of Forensic Sciences later listed his cause of death as complications from toxic effects of insulin and his manner of death as undetermined.

Chambers County Sheriff and Skyler Rocz. (Chambers County Sheriff's Office)(Chambers County Sheriff's Office)

Rocz — who had become a detective in November 2022 and was on her first week of on-call duty — said details at the scene struck her as incongruous. Sarah Hartsfield, Joseph’s wife and a former U.S. Army sergeant, told investigators she had found him unresponsive at about 1 p.m. but did not call 911 for roughly an hour. Rocz also described what she saw as unusually flat and inconsistent emotional responses from Sarah while at the hospital.

Digital Evidence and a Broader Probe

Rocz’s review of Joseph’s phone uncovered messages sent the morning of Jan. 7 that included his driver’s license, a wedding photo, bank-account details and an Apple Legacy Contact key that would grant access to his device after his death. Using data from Joseph’s device, Rocz obtained a warrant for Sarah Hartsfield’s phone.

Joseph Hartsfield. (KPRC)(KPRC)

According to Rocz’s testimony, Sarah’s phone activity contradicted her written statement that she had been asleep and sedated following surgery. Investigators found hourly phone activity, deleted internet searches and text-message threads that showed repeated arguments and a desire by Sarah to end the marriage. Prosecutors argued at trial that those findings supported their theory that Sarah administered a fatal dose of insulin; defense lawyers countered that Joseph likely mismanaged his diabetes.

Past Allegations Revisited

Rocz’s probe also uncovered troubling elements of Hartsfield’s past: a 2018 fatal shooting of a former fiancé that Hartsfield says was self-defense, a protection order involving her two youngest children, and allegations of a murder-for-hire plot tied to Hartsfield’s third and fourth marriages. Hartsfield denies involvement in those prior allegations and has not been charged in connection with them. An FBI agent said he corroborated elements of the alleged plot, but federal prosecutors declined to bring charges after a witness recanted involvement.

David Bragg. (KPRC)(KPRC)

Indictment, Trial and Sentence

Rocz presented her findings to the district attorney’s office, and authorities indicted Sarah Hartsfield on Feb. 3, 2023. Following a trial that examined both the immediate circumstances of Joseph’s death and Hartsfield’s background, a jury convicted Sarah Hartsfield of first-degree murder in October 2023. She received a life sentence.

"I was told I was beating a dead horse," Rocz told NBC’s "Dateline." "I just had to disagree."

Rocz, now an investigator with the Chambers County District Attorney’s Office, said she felt a deep relief when the verdict came in. The case highlights how digital forensics, careful follow-up and persistence by a recently minted detective helped reshape an investigation that earlier drew skepticism from supervisors.

Sarah Hartsfield in court. (Rebeccah Glaser / Dateline)(Rebeccah Glaser)

Note: Sarah Hartsfield maintains her innocence in Joseph Hartsfield’s death and disputes allegations from the past. This article reports the findings and outcomes of the official investigation and trial.

This article was originally published on NBCNews.com.