Man and Woman Hatched Plot to Poison Multiple Exes With Cyanide: DA

The arrests of Paul Van Duyne and Andrea Whitaker went down this week in Madison, prompting several hazmat investigations in the process.

"It does appear that this defendant and Mr. Van Duyne have started dating and apparently created this plot to kill his ex girlfriends by poisoning them with cyanide valium poisons," Dane County Deputy District Attorney William Brown said in a bail hearing for Whitaker, per WMTV.

Per jail records, Van Duyne was charged with one count of stalking and two counts of attempted first-degree murder, while Whitaker has been charged with harboring and aiding a felon and one count of attempted first-degree murder.

The investigation has been ongoing for a month and began after a woman saw people surrounding her car in a Costco parking lot in Middleton. When she approached the group, one of the people standing near her car said they saw someone break into the vehicle. The woman then took a sip from her water bottle and quickly spat it out, as it tasted off.

Then, the same thing happened again in just a matter of weeks. The woman called 911 this time, after smelling something odd in her water bottle.

"Ultimately, that water bottle was taken to the crime lab and it was learned that there was cyanide placed in that water bottle," said Brown.

Another woman in the Rock Country area found herself in a similar situation; she, however, ended up in hospital. Both women had previously dated Van Duyne.

"It does appear that Mr. Van Duyne was perhaps the actual person that was entering both victims vehicles and putting the cyanide in the water bottles," Brown claimed, with prosecutors saying that a plastic bag likely containing hydrogen sulfide was also placed in one of the vehicles, causing the victim's minor sister to get sick.

All in all, prosecutors have claimed there are five different instances of attempted poisoning -- including one in which the suspects allegedly placed a toxic plant protein known as abrin in the ventilation of one of the victims' cars.

One of the victims told police she had a "casual" and "sexual" relationship with Van Duyne about two years ago, before he started dating a woman since identified as Whitaker. The woman allegedly even warned Van Duyne that Whitaker seemed "dangerous and toxic."

Van Duyne was arrested after he showed up to the second woman's home on Sunday evening, while a trail camera was also allegedly pointed pointed at the house.

During the hearing, Brown said Van Duyne called Whitaker from jail and asked her to remove evidence from the home -- including a computer and, likely, poisons. Whitaker, per Brown, also had searches related to cyanide on her computer, including, "Does potassium cyanide cloud water?",  "Sodium cyanide odor, sodium cyanide," "What does cyanide look like?" and "Cyanide lethal dose?"

"In at least Rock County, putting cyanide powder in the air vents, I think this defendant's involvement is absolutely clear in that she is likely the brains of the operation in figuring out how to do this," Brown said of Whitaker, who he claimed also has a background in pharmacology. He also called conversations between the two suspects "extraordinarily concerning."

"The evidence seems to be so documented and clear of what the plan was, in which these two women have almost lost their lives, so we're not speculating," he added.

A search of Van Duyne's properties also found rosary pea seeds, which the CDC notes are a source of abrin, as well as other material used to produce poison.

The investigation also led to the hospitalization of seven Wisconsin Department of Justice DCI agents, due to exposure, said Brown.

Whitaker was given a $750,000 bond and ordered to have no contact with Van Duyne if he is released.