OnlyFans Star Plunges to Her Death From Hotel Balcony While Filming Threesome

An OnlyFans porn star’s hotel balcony threesome in Brazil took a tragic turn when she plunged to her death.

Anna Beatriz Pereira Alves -- AKA "Anna Polly" -- was found dead in the ground-floor courtyard of the upscale Mont Blanc Apart Hotel, just northwest of Rio de Janeiro, last week ... according to The Sun.

Brazilian authorities are digging into details of her death ... as her two male scene partners are telling totally different stories about what went down during their wild filmed hookup.

The costars, who are also OnlyFans performers, were released after questioning -- but the Baixada Fluminense Homicide Unit hasn’t ruled out foul play just yet.

Cops are also checking hotel CCTV, grilling the staff, and digging through Anna’s phone as they piece together what really happened.

The autopsy results aren’t out yet, so it’s still unclear if Anna had drugs in her system or if there were signs of sexual violence.

Anna’s boyfriend, Pedro Henrique -- who wasn’t part of the incident -- took to social media, heartbroken and hoping investigators get to the bottom of what happened.

Anna was 27.