Just saw this as well.
First, Lisa Darden is not a suspect in her partner's death. It's very confusing, and there is a lot of innuendo, mainly because Darden had become a beneficiary of her partner's insurance shortly before she died.
It seems to be just from a detectives note, that in his own opinion, it wasn't an accidental overdose. Lisa Darden's partner had an oxycodone prescrption, was "reportedly" struggling with abusing that medication. There is no clarification about how it is known that the partner had an abuse problem. I'm not saying she didn't, the article just doesn't clarify how it was known that the Lisa Darden't partner was abusing her medication. IMO, "reportedly" is doing a lot of heavy lifting here with zero source identified.
Mom of Kouri Richins, Utah grief author accused of poisoning husband, may have had a role in death, officials say
"A detective with the Summit County Sheriff's Office also said that Kouri Richins' mother, Lisa Darden, is connected to the "suspicious overdose" death of Darden's former partner in 2006...Darden has not been charged with any crime..."
...The search warrant affidavit said that as investigators interviewed people close to the couple [Eric and Kouri Richins], they learned that in April 2006, Darden's partner died unexpectedly.
The partner was a woman "with whom she was having a romantic relationship" and lived with, according to the document.
An autopsy showed that the woman's "immediate cause of death was a drug poisoning from an overdose of oxycodone," the document said.
Further investigation showed that Darden had been named as the beneficiary of the woman's estate "a short time before her death," it said.
The detective wrote in the document that the woman did have prescriptions for oxycodone and reportedly struggled with abusing her medication.
"She, however, was not in a state of recovery from addiction at the time of her death," the detective wrote. "Based on my training and experience, this would likely rule out the possibility of an accidental overdose."