(NewsNation) — A letter allegedly written by Brian Laundrie’s mother has been called into question before a judge.

Pat Reilly, the attorney who represents Gabby Petito’s parents, Joseph Petito and Nichole Schmidt, claims the letter mentions “burying a body” and to “burn after reading.”

“There’s some pretty extreme things she said in there that, without having the letter here to quote it I don’t want to say, but I will simply tell you that there’s some pretty extreme things that were contained within that letter,” Reilly told NewsNation affiliate WFLA in June. “I will tell you, by the way, that on the envelope that contained the letter, the words ‘burn after you read this’ were written.”

Authorities say Petito was strangled to death while on a cross country trip by Laundrie, who was her boyfriend at the time. Laundrie was found dead of a self-inflicted gunshot wound weeks later.

It appears that Reilly wants to use the letter, if it exists and is reportedly written by Roberta Laundrie, in a deposition. According to a court filing from December, the letter revealed that Roberta had offered to lend a shovel to Brian to help him bury the body.

Last March, Laundrie’s parents tried to get a judge to throw out a civil lawsuit brought against them by Petito’s parents. The lawsuit accuses the Laundrie family of knowing their son killed Petito and working to help him flee the country.

Judge Hunter W. Carroll ruled against the Laundries’ motion to dismiss the lawsuit. Carroll also denied a motion to limit the scope of the Laundries’ depositions, which are expected to be taken in the coming months.

The depositions will mark the first time the parents of Petito and Laundrie will be in the same room since Petito’s murder and Laundrie’s suicide in 2021.