SALT LAKE CITY — A couple who recently moved to Utah from Switzerland may have planned a murder-suicide together that left them and two children dead, according to newly unsealed search warrants.

Investigators found messages between the husband and wife about “when this tragic incident would take place,” police said in court documents unsealed Wednesday.

Jessica Griffith, 42, may have had terminal ovarian cancer and had little time left to live, according to messages and online searches detailed in court documents. Family members told investigators she had suffered from depression, and her husband Timothy Griffith, 45, was violent and may also have struggled with an undiagnosed mental illness, the search warrants state.

Police declined to answer additional questions about the documents.

Timothy Griffith’s stepmother, Linda Sue Prater, said Wednesday she never knew him to be violent or suffer from mental illness, though he hadn’t been in close contact with family members after moving back to the US in July, she said.

The family of four was found dead in November, just months after Timothy Griffith’s job with Nestle took them from Switzerland to Mapleton, Utah, about 55 miles south of Salt Lake City. Police also found the bodies of their 5-year-old son Alexendre Griffith and Jessica Griffith’s 16-year-old daughter Samantha Badel.

Timothy Griffith shot all three with one gun before killing himself with a different weapon, a shotgun, according to police. He also killed the family dog, police said.

Family members are still grappling with what happened and searching for answers, said Prater, who lives in Hanceville, Alabama. He had always been a steady, calm man who loved children and animals, she said.

“He just never seemed like the type that would do something like that,” Prater said. “A thing like this eats at you every day because you don’t know what happened.”

He had done some unusual things recently, like registering his cell phone under a made-up business name and saying he didn’t want anyone to know where he was, she said.

Timothy Griffith moved to Switzerland after falling in love with a Swiss exchange student who stayed with the family during his high school years in Granite City, Ill., she said. The couple divorced after having three children together and he married Jessica Griffith, who was also from Switzerland, about six years ago, she said.