Wisconsin pair charged in alleged plot to stalk, poison, and kill dating app liaisons

A Wisconsin boyfriend and girlfriend have been charged with attempted murder for allegedly trying to poison two women the man previously dated after meeting them online, authorities said.

Paul VanDuyne Jr., 43, and Andrea Whitaker, 41, have each been charged with attempted murder, aggravated battery, recklessly endangering the public and stalking, according to criminal cases filed in the Madison, Wisconsin region.

On Friday, they each appeared in court separately in Janesville, in Dane County, which also is home to the state capital. Bail was set at $10 million for VanDuyne, who prosecutors said has access to substantial resources, and $4 million for Whitaker.

Pleas were not entered and each remained in custody, according to jail records. The defendants have separate lawyers, who did not respond immediately to requests for comment.

One of the two victims — each of whom met VanDuyne on a dating app and saw him only a few times — described an experience discovering a stranger she later realized was Whitaker crouched next to her vehicle in her garage in April.

The woman is identified in redacted court records as the victim from Dane County; the other woman is identified as the victim from Rock County. The Dane County woman said Friday in court that she met VanDuyne more than a year ago, went on two dates with him, and told him she wasn’t interested in seeing him again.

“I was never his girlfriend, yet he and Andrea developed the delusion that I was,” she said in court Friday. “This delusion was so strong, they tried to murder me. Their actions and motivations are disconnected from reality. Both have shown their capacity for evil.”

Appearing at VanDuyne’s hearing, the woman said that after discovering the allegations against the couple, she has people stay with her overnight, installed a security system, and hides her vehicle.

“I need the court’s protection,” she said. “The community needs the court’s protection.”

Prosecutors said VanDuyne met Whitaker online roughly during the same time he dated the victims and carried on a relationship virtually as she took courses in the field of pharmacology away from the area.

Upon her completion of courses, she moved nearby, and the two met in person in spring, according to narratives presented in case documents.

VanDuyne graduated from Princeton University more than 20 years prior, the institution confirmed. He had a career as a mechanical engineer, his lawyer said in court on Friday. Documents in the Rock County case say he was recently divorced and started dating the victims after meeting them on dating apps or sites that were not named.

When he connected with Whitaker, the two embarked on a plot against the victims, prosecutors said.

The victim from Rock County came to the attention of authorities in early May when a doctor from the Wisconsin Poison Center reported that a woman was hospitalized with thallium in her system, the court documents state.

Thallium was once commonly used to kill rodents. Largely because of accidental poisonings, it has been banned from household use in the U.S. since 1965 and commercially since 1975.

The doctor, identified only by a last name, is quoted as saying, “The only way a human could have this amount of thallium in her system is if they were intentionally consuming it.”

Prosecutors said the victim reported no suicidal action and struggled to think of anyone who would try to poison her — the names she came up with were vetted — until VanDuyne came to mind, according to the documents from Rock County.

She told detectives about texts she had received in early 2025 texts from the man she knew only as Paul when they dated starting nearly two years before, they state.

She gave investigators his number, and they started looking at VanDuyne earlier this month, according to the court documents.

She said he had sent her texts in the spring after months of no contact. In them, the Rock County victim said, he called her “evil” and blamed her for causing his girlfriend, Whitaker, to kill herself when she discovered their dating history, the documents state.

Whitaker did not kill herself.

In fact, court documents allege, she was integral to the plot to kill the two other women VanDuyne had dated, and they worked together to taint water bottles and vehicles with poisons they procured or, in one case, made from scratch.

In the May incident that sent the Rock County victim to the hospital, the woman took her middle-school aged sister to the movies but both became ill, according to the documents. The victim took her vehicle to a dealership, where workers reported a noxious smell and tossed out a storage tote they said contained an unknown substance, they said.

Because the woman and her sister described a smell of rotten eggs, detectives concluded the substance was hydrogen sulfide, a toxic gas.

Rock County Sheriff Curtis said the Rock County victim was still in a wheelchair as a result of her poisoning. Without the medical care she’s received — including an antidote flown overnight from California — she most likely would have died, he said.

The alleged plot impacted the other victim, the woman from Dane County, not long afterward, in mid-May, when bystanders reported someone breaking into her vehicle at a Costco parking lot on two separate occasions, according to the documents.

One witness at the Costco parking lot reported seeing a man get into a Chrysler Pacifica minivan that was traced back to VanDuyne, authorities said in the documents.

After one of the incidents, the victim reported drinking bottled water she left in her vehicle and noticing in tasted terrible, the court documents state. The water tested positive for cyanide and thallium.

After realizing the two victims may have the same perpetrators, authorities took a second look at the Rock County victim’s vehicle and concluded it was the subject of a break-ins or attempts with markings similar to those made in the Costco attempts, the documents state.

Detectives got a judge’s permission to track VanDuyne’s movement and found him traveling to the Rock County victim’s residence, according to the documents. After that trip, authorities allege, they found a trail camera hung on a tree across from the victim’s home.

In other instances the couple worked together to use cyanide, thallium, and abrin in multiple attempts to poison the victims, once even putting a powdery substance in the ventilation system of a victim’s vehicle, authorities said in the court documents.

Abrin can be made by grinding the seeds of rosary peas, authorities said in the documents.

On Thursday, a search of VanDuyne’s minivan turned up a tan bag with multiple vials inside, the court documents say. Authorities found rosary peas in the bag and a seed grinder at his home, the documents state.

An FBI hazardous materials team was called to help with the search, and members took an active part multiple times, the documents say.

The defendants were expected to appear in Rock County court next week to face charges of attempted murder and stalking for VanDuyne and attempted murder and aiding a felon for Whitaker.

VanDuyne is due in Dane County court again Aug. 4. She is scheduled for an appearance there July 2.