LANSDOWNE STATION — RCMP officers investigating the disappearance of two Nova Scotia children say that some of the people interviewed by police for the case have taken lie detector tests.
Four-year-old Jack Sullivan and six-year-old Lilly Sullivan disappeared on May 2 from their residence in Lansdowne Station, N.S., about 60 kilometres east of Truro. The case has gripped the province, with hundreds of trained volunteers combing through the densely wooded area surrounding the family home. Search and rescue teams have been assisted by helicopters, drones and thermal imaging devices.
In a virtual news conference on Wednesday, the RCMP would not discuss results of the lie detector tests, known as polygraphs, or say how many of the 54 people interviewed by police had sat for one. Polygraphs measure the fluctuations of a person's nervous system as they answer questions, in order to assess the truthfulness of responses.
"The truth verification unit is engaged," Cpl. Guillaume Tremblay told reporters about one of several RCMP units assisting in the case. "There's multiple facets to those investigations and those experts are examining every question and answer that those individuals are providing and it could guide the investigation."
The Mounties have said that family members of the missing children are among those who have been interviewed by police. Daniel Martell, the children's stepfather, told The Canadian Press on May 28 that he had sat for a lengthy interview with police and offered to take a polygraph.
"I passed my polygraph exam," he said at the time.
RCMP have declined to confirm or deny whether they gave Martell a polygraph.
Thomas Mauriello, a U.S.-based forensic consultant and expert on polygraphs, said in a recent interview that it's doubtful police would share the results with someone who had taken the test. Those tests are generally not admissible in court as evidence, but police continue to use them to help guide investigations, he said.
"It's often used in a criminal case to screen out people .... The polygraph is a great investigative tool, but that's all it is. It just provides you with some information to help you to decide how much time or effort you want to put into a certain aspect or person in a case," he said.
Mauriello said polygraphs measure changes to the sympathetic nervous system, which prepares the body for fight or flight responses.
"When you perceive a threat, whether it be a physical or a psychological threat, your sympathetic nervous system takes over your body to prepare you to fight or run away from that threat. That's what the polygraph is measuring," he explained.
Meanwhile, Tremblay said that police recently searched "every aspect" of the trailer where the missing children lived with their mother, her partner and the couple's infant. Police also searched outbuildings on the property and nearby septic systems, wells, culverts and four abandoned mine shafts.
He didn't comment on whether searchers found evidence relevant to the investigation.
In a news release, the Mounties said Wednesday they've been granted judicial authorizations to seize and examine "materials and devices" that could potentially help their investigation. A court official said all of the documents are sealed.
The RCMP say at least 11 units are working on the case, including the major crime unit, forensic services, the truth verification section, police dog services and the behavioural sciences group.
Tremblay said the Mounties are encouraging people to come forward with more information, adding they've received 488 tips to date.
"We're making sure that nothing is missed. We're committed to doing what is necessary to locate Lilly and Jack, which may take longer than we all had hoped," he said.
This report by The Canadian Press was first published June 11, 2025.
— Story by Michael Tutton in Halifax.
The Canadian Press
