The son of the 'Pawn Stars' personality died on Jan. 19
Rick's representative, Laura Herlovich, tells PEOPLE that Adam's death was due to a fentanyl overdose.
TMZ was the first to report the news of Adam's death at age 39 on Jan. 19. At the time, it was only reported that Adam had overdosed.
The Las Vegas Metro Police Department also confirmed to TMZ that there was an open investigation into his death.
At the time, Herlovich shared a statement with the Las Vegas Review-Journal on behalf of the Harrisons, saying, "Our family is extremely saddened by the death of Adam. We ask for privacy as we grieve his loss."
Rick also shared some throwback photos with his son on Tuesday, writing beside the images: "Amazing memories"
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Adam was the second child of Rick and his ex-wife, Kim. He is the younger brother of Corey Harrison. Rick remarried his second wife, Tracy, and the couple welcomed one son, Jake.
Adam did not appear on Pawn Stars alongside Rick and Corey. However, Adam reportedly worked at Gold & Silver Pawn before the unscripted program's 2009 premiere.
If you or someone you know is struggling with substance abuse, please contact the SAMHSA helpline at 1-800-662-HELP.
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