It's been 9 months since the tragic death of Audrina Patridge's 15-year-old niece, Sadie, and cops are working to find out who may have supplied the drugs that killed the young girl.
Law enforcement sources tell TMZ ... Sadie's death has officially been ruled a narcotic overdose. However, they've not yet determined the manner of death as there's currently an investigation for possible criminal charges.
Our sources say cops want to figure out how Sadie was able to obtain the drugs.
One source tells us ... Sadie was able to buy Percocet through Snapchat, and it was laced with fentanyl. Of course, if that's the case ... cops will work to determine who sold it to the young teen and charges will likely follow.
You'll remember, the man who supplied Mac Miller with a fatal dose of fentanyl was sentenced to 17.5 years in May of last year after Mac's 2018 death ... so it's very much a serious offense.
It was back in February when Audrina announced the heartbreaking news that Sadie had died, writing, "My beautiful niece is now in heaven. I know Its not goodbye forever, but it is the hardest to say goodbye for now. We will miss you and cherish every single moment we had with you. Rest in peace Say Say!! We love you forever & ever!"
Sadie's death is yet another example of an extremely dangerous fentanyl issue. Her family set up a GoFundMe in Sadie's honor, with funds to be directed to the Sadie Raine Foundation, established to help teens and their families.