The Los Angeles Medical Examiner’s office said in a report that Rich died on January 8 from the “effects of fentanyl.” His death was considered to be accidental.

When his body was found in his home earlier this year, Rich was only 54 years old. At first, the reason for his death wasn’t known until more research was done, but sources in law enforcement told TMZ that there were no signs of wrongdoing when they found his body.

Rich was best known for his role on the 1970s TV show Eight Is Enough as Nicholas Bradford, the youngest kid of Tom Bradford (Dick Van Patten), and his wife, Diana Hyland.

Willie Aames wrote an emotional post after the actor who played Rich’s brother on the show died. “This morning [my wife] Winnie woke me with the heartbreaking news of Adam Rich’s passing,” he wrote. “I’m gutted. Adam was more than a colleague. He was very much my only little brother. A lifelong friend.”

Rich’s on-screen wife, Betty Buckley, also thought of him after he died too soon.

“Adam Rich was a light and my young pal for the four seasons. I was blessed to work with him on Eight Is Enough. I adored him and loved working with him in our scenes together on the show. He was so sweet, funny, fresh, and natural. He brought a lot of joy to all of us on the show and to our audiences. Adam and I have remained friends all of these years. His love and support have always meant a lot to me.”