The sister of a Texas man whose wife is accused of killing him with a fatal dose of insulin testified Tuesday that before he died in 2023, she had grown increasingly worried about him after she learned of Sarah Hartsfield’s ominous past.

Jeannie Hartsfield took the stand in a courtroom east of Houston on the first day of testimony in Sarah Hartsfield’s murder trial in the death of Joseph Hartsfield, 46, and described learning of an alleged murder plot targeting another husband.

The revelation came after Sarah Hartsfield, who has pleaded not guilty in Joseph Hartsfield’s death, disclosed to her sister-in-law that she’d also fatally shot a former partner in self-defense, Jeannie Hartsfield testified.

Jeannie Hartsfield initially didn’t think much about the self-defense shooting, she testified. But she said she grew very concerned after Sarah Hartsfield told her that the FBI had investigated her in an alleged murder plot.

“Things didn’t seem right,” Jeannie Hartsfield said on the stand.

The apparent plot referred to allegations that Sarah Hartsfield tried to enlist her fourth husband to kill her third husband’s new wife in Sierra Vista, Arizona.

The third husband, Christopher Donohue, made the allegations, which Sarah Hartsfield has denied, in an affidavit in support of a protection order that he filed in 2021. The fourth husband, David George, has said he had no intention of carrying out the murder.

A Sierra Vista police spokesman has said a federal agent asked the police department to monitor Donohue’s home with a “close patrol.”

No charges were filed in the case. The FBI hasn’t commented on the case.

Donohue and George have both been subpoenaed to testify in Sarah Hartsfield’s murder trial.

The self-defense shooting referred to the 2018 killing of Sarah Hartsfield’s fiancé, David Bragg. At a bond hearing in 2023, Sarah Hartsfield testified that she fatally shot Bragg in self-defense after an argument over her third husband’s decision to visit their children in Minnesota outside of normal visitation.

After Sarah Hartsfield was indicted in Joseph Hartsfield’s death, the county attorney who cleared her in Bragg’s killing — he previously said she had “no reasonable possibility of retreating” — said the case was “active” again.

Douglas County Attorney Chad Larson hasn’t responded to requests for comment on the status of that investigation.

Tuesday’s testimony came after prosecutors began laying out their case against Sarah Hartsfield, whom Chambers County Assistant District Attorney Mallory Vargas described as a performer whose “true identity” was concealed by her whirlwind relationship with Joseph Hartsfield.

Within a year, Vargas said, the pair’s relationship had soured. As Joseph Hartsfield was preparing to leave her, Vargas alleged, Sarah Hartsfield intentionally caused his death.

Officials have said Joseph Hartsfield — who had diabetes — died Jan. 15, 2023, from complications of toxic effects of insulin, the lifesaving medicine that helps regulate blood sugar and has been used as a difficult-to-detect murder weapon.

Joseph Hartsfield’s manner of death was listed as undetermined.

Defense lawyer Case Darwin said prosecutors were “telling a story” and suggested that Joseph Hartsfield’s death could be linked to poor management of his health issues.

He didn’t take care of himself, Darwin said, and he’d previously been hospitalized for diabetes-related complications. Joseph Hartsfield had administered his own insulin, Darwin said, and there was no evidence showing who gave him the fatal dose.

Sarah Hartsfield talks a lot, Darwin said, and she is “adamant she didn’t do this.”