A Harvard professor says HLN host Nancy Grace‘s relentless questioning of a Florida mother contributed to the woman’s suicide three years ago.

In the days after two-year-old Trenton Duckett went missing in August of 2006, Grace began extensive coverage of the case, eventually speaking by phone to the boy’s mother, Melinda Duckett, who is, to date, the only suspect in his disappearance. The boy has never been found.

Dr. Harold Bursztajn, a clinical professor of psychiatry, wrote in a filing last week that Grace “struck a highly accusatory tone” in the interview.

“Her apparently unanticipated public humiliation on the nationally televised program in question was a substantial contributing cause of her suicide,” Dr. Bursztajn wrote.

21-year-old Duckett shot herself in the head the day after the Grace interview. A suicide note was later found.

The findings from Dr. Bursztajn are contained in the wrongful death lawsuit filed by Duckett’s family.