Priscilla Presley speaks out following the death of her grandson Benjamin

Priscilla Presley is opening up about the tragic death of her grandson, Benjamin Keough.

The 75-year-old actress, who was married to Elvis Presley from 1967 to 1973, took to Facebook on Wednesday, admitting that the days since Benjamin's death on July 12 have been "some of the darkest days" of her family's life. The Los Angeles County Medical Examiner confirmed to ET at the time that Benjamin's cause of death had been ruled a suicide. He was 27.

"The shock of losing Ben has been devastating. Trying to put all the pieces together of all the possible whys has penetrated my soul," Priscilla wrote. "Each day I wake up I pray it will get better. Then, I think of my daughter and the pain she is going through as she was a doting mother."

"Ben's father, Danny, who is completely lost, as Ben was his only son," she continued. "Riley, so loving and so close to him; Harper and Finley, who absolutely adored Ben. Navarone, who struggles deeply with loss and death. Rest In Peace Ben, you were loved."

Benjamin was the son of Danny Keough and Lisa Marie Presley (Priscilla and Elvis' only child together). In addition to his parents, Benjamin is survived by his siblings -- sister Riley, 31, and 11-year-old twins Finley and Harper.

A rep for Lisa Marie told ET last week that she has been "completely heartbroken, inconsolable and beyond devastated" following the death of her son.

"She's trying to stay strong for her 11-year-old twins and her oldest daughter, Riley," the rep added. "She adored that boy. He was the love of her life."

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