The adult film actress -- who got her start in the industry way back in the mid-2000s -- passed away Thursday in Cuyahoga County ... this according to online records that confirm her body was received by the Medical Examiner's office that day from Parma, OH.

A rep for the Parma Police Department tells TMZ ... Kagney appears to have taken her own life -- something confirmed by friends of hers who've now started a GoFundMe on behalf of her mom, Tina.

The organizers of the GFM say the cash raised will go toward costs Tina has incurred in properly laying KLK to rest, including memorial services. The GFM -- which has a goal of $8,000, and has raised just less than $6k at this point -- will use any leftover cash and donate it to a local animal rescue charity ... something her friends say she would've wanted.

The two women behind the GoFundMe say they're fitness studio owners -- ones that Kagney would apparently frequent in the Cleveland, OH area -- and they say she had started one of her own as well in Akron ... noting it was the first pole studio of its kind around there.

The GFM has kind words to share, writing ... "Kagney was a woman who wore many hats; she was a performer, a singer, a dancer, a daughter and a friend. She first came to our Cleveland studio in November of 2019, freshly moved out of L.A., rearing and ready to jump back in to pole, in a brand new community where she knew no one and no one knew her."

The 2 women organizing the GFM go on to claim Kagney had personal problems too, saying ... "Unfortunately, despite all of her many impressive accomplishments and talents, Kagney struggled with mental health issues as the years passed by."

They continue ... "Even in her darkest days, however, she still showed up to the studio, always ready to learn, contribute, better herself in whatever small way she could manage. As alone as she undoubtedly felt within the confines of her own head, she continued to make an effort to show up for her friends and the community who cared about her. She fought her own battles with the same tenacity and drive she showed in every other area of her life, with as much strength as she could."

Kagney had starred in countless adult films and programs throughout her lengthy career -- and she was a decorated performer in the porn biz ... having won AVN awards and other accolades for her work. In addition to porn, she also modeled a lot -- including for Penthouse -- and danced at exotic clubs as well.

One of her last posts shows her recently vacationing in Florida, where seemed to be in good spirits. Kagney was only 36.

RIP