'Young and the Restless' Star Kristoff St. John's Cause of Death Deferred Pending 'Additional Investigation'

Young and the Restless star Kristoff St. John's cause of death has been deferred.

According to an autopsy report obtained by E! News, the Los Angeles County Coroner is postponing a cause of death for St. John, who passed away Sunday at the age of 52, until an "additional investigation" is completed.

The autopsy was completed on Monday, just one day after his death, though the outlet notes that it "offers little insight" into St. John's manner of death.

St. John, who portrayed Neil Winters on the CBS soap opera since 1991, was found unresponsive by a friend in his San Fernando Valley home on Sunday, Feb. 3. Police and paramedics pronounced him dead upon their arrival. They noted that no signs of foul play were evident at the scene.

The actor's ex-wife, Mia St. John, had seemingly confirmed his death in a since-deleted tweet, just hours before news broke on Monday, Feb. 4.

St. John's death came just years after he lost his son, Julian, whom he shared with his ex-wife. While seeking treatment at a mental health facility in 2014, Julian died by suicide. In the years that followed, St. John was hospitalized after undergoing a mental health investigation. According to TMZ, he had voluntarily checked himself into UCLA Medical Center in January for struggles with depression.

"To all of mi (sic) IG peeps. Thanks for throwing out a life preserver. Words cannot express the gratitude that I feel to have so much love that you bathe me in…anoint me with…cloak me with. I am humbled," he wrote in an Instagram post in 2017. "Life is precious. I look forward to continuing this journey together with all of you…us. Because at the end of the day, at the magic hour, we are warmed with an all knowing presence of light and love. My heart beats to the music of our creation. You are an integral piece of my personal spiritual puzzle, as I hope I am to yours. I love you…forever. #gratitude #friends #life #journey #love #yr #cbs."

In the wake of his death, St. John's fans and co-stars have flocked to social media to pay tribute to the actor.

"An infinite number of hearts are broken because of the passing of Kristoff St. John," his Young and the Restless co-star Eileen Davidson said in part in a statement to PEOPLE. "Kristoff was a loving kind generous sweet hilarious gifted human. He left an indelible mark on all who were blessed to know him. I am so grateful to have been able to work with him and laugh with him. My deepest condolences go out to his family and especially his children, who I know he loves so much."

St. John is survived by his two daughters, Paris and Lola.