An incident that left a couple and their two children dead might have been a murder-suicide planned by the parents, the Associated Press reported.

Information that has emerged from newly unsealed search warrants indicates that Jessica and Timothy Griffith, who had recently moved to the U.S. from Europe, might have wanted to put an end to their family.

Messages exchanged by the husband and wife and found by investigators said “when this tragic incident would take place,” police said in court documents unsealed Wednesday.

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Jessica, 42, appears to have been suffering from terminal ovarian cancer, with only a short time left to live. Family members told investigators that she also dealt with depression and that Timothy, 45, had violent tendencies, possibly stemming from an undiagnosed mental illness, according to a search warrant.

The four family members were found dead in November; just a few months before, Timothy’s job with Nestle had led the family to move from Switzerland to Mapleton, Utah.

Police say Timothy shot his wife and two children — their 5-year-old son Alexandre and Jessica’s 16-year-old daughter Samantha Badel — before killing himself with a shotgun, a different weapon than he allegedly used on his family members.

Police said Timothy also killed the family’s dog.

Timothy’s stepmother, Linda Sue Prater, who lives in Alabama, said Wednesday that she didn’t think he was prone to violence or suffering from any mental illness. She described her stepson as a calm man with a fondness for kids and animals. However, Prater added that Timothy had not kept close contact with his family since leaving Switzerland in July.

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

However, Prater said Timothy had done things recently that were out of character and could raise suspicion, such as registering his cell phone under a fake name and saying he didn’t want anyone to know where he was.

Timothy, who was originally from America, had moved to Switzerland after falling in love with a Swiss exchange student, whom he married and had three children with. They later divorced, and Timothy married Jessica about six years ago, Prater said.

Parents might have planned their family’s deaths in a grisly multiple murder-suicide, court documents say AP Photo/LM Otero