Kouri Richins, the Utah grief author who faces charges for allegedly killing her hubby with a fentanyl-laced Moscow mule, has been accused of witness tampering after officials found a handwritten letter in her jail cell that relayed instructions about where her family should say that her spouse got the drugs that killed him, prosecutors said.

The writer — who allegedly killed Eric Richins, 39, last year — instructed her mom, Lisa Darden, to have Ronald Darden, Kouri’s brother, to falsely testify that Eric received drugs and pills from Mexico, Fox 13 Now reported.

Deputies found the letter inside Richins’ cell, where she is being held on charges of first-degree aggravated murder and second-degree possession of a controlled substance with intent to distribute, according to the outlet.

The search was conducted after the 33-year-old woman suffered a seizure when she was given a wrong medication at the Summit County Jail, the Daily Mail reported.