(NEW YORK) — Domestic partners are “increasingly likely” to use chemical and biological toxins to kill or harm their partners, a trend so alarming that the Department of Homeland Security issued a warning to law enforcement.

The warning came in a January intelligence note, obtained by ABC News, that said people intent on harming or killing their domestic partners are turning to poisons like cyanide or ricin to do it, which are “often sourced from online black markets or made at home.”

“The use of chemical and biological toxins in domestic violence cases poses a significant challenge for detection and prosecution due to the often subtle and delayed onset of symptoms,” the intelligence note said.

The document highlighted as an example the case of a Colorado dentist convicted of first-degree murder last year after gradually poisoning his wife with a mix of arsenic, cyanide and tetrahydrozoline, the latter a medication commonly found in over-the-counter eye drops. The dentist secretly dosed his wife by adding the poisons to her protein shakes, according to prosecutors, resulting in her being hospitalized three times in a 10-day span, and then gave her a fatal dose of cyanide while she was ill in the hospital.

“Incidents using chemical or biological toxins to harm or kill are driven by several factors including accessibility of online information, ease of obtaining certain chemicals, and perceived difficulty in detection,” the DHS note said. It also listed an additional 16 cases in the U.S. since 2019 in which individuals were accused or convicted of poisoning current or former spouses, domestic or romantic partners, or family members, 10 of which resulted in the victim’s death.

Substances most often used in domestic poisoning incidents are antifreeze, eye drops, the synthetic opioid fentanyl and the prescription medication colchicine, as well as cyanide and the chemical element thallium, according to the note.

“These substances are often chosen for their ability to mimic natural illnesses, complicating detection and investigation,” the note said.

“If the trend of using chemical or biological toxins to kill or harm continues, we may see an increase in fatalities and long-term health consequences among survivors,” as well as an increase in the “need for specialized training and equipment for first responders,” according to the DHS note.

“The recurring use of these toxins by domestic partners highlights the need for more awareness, regulation, and forensic expertise to address this trend in domestic partner violence,” the note further said.

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