Sofia Gatti, the daughter of late boxing legend Arturo Gatti Sr. and sister of late 17-year-old up-and-comer Arturo Gatti Jr., claimed her brother was "mysteriously killed" and said she received confirmation that authorities were now investigating his death as a homicide, according to an update on a GoFundMe page.

Sofia wrote that her family "received documentation" that her brother's death was now being treated by investigators as a homicide after it was initially reported that he died by suicide, the same as his late father 16 years prior, in the latest update shared on the fundraiser, which was launched “hire an investigative team to get autopsy, toxicology, reports…. To find out what really happened…”

"We have received documentation from authorities indicating the case is being investigated as a homicide," Sofia wrote. "I want to thank everyone who has supported the ongoing effort to uncover the truth about my brother, Arturo Gatti Jr.’s death.

"To date, several legal and investigative steps have been taken in Mexico, Canada and the United States. Family representatives and legal counsel have filed for the preservation of Arturo’s remains, secured investigative access, and initiated forensic reviews."

"Our long-term goal is to unify all legal efforts across the countries involved, ensuring a clear and coordinated path toward justice," she added.

Arturo Gatti Jr. was previously reported to have been found hanged in his apartment earlier this month. Actor and stuntman, Chuck Zito, who worked as his father's bodyguard, confirmed his passing in a since-deleted post shared on his Instagram account on October 8.

Gatti's longtime coach, Moe Latif, also confirmed his passing in a post shared on his Instagram Story.

"It is unfortunately not a rumor or a joke. Arturo is gone. I'd appreciate if you stop reaching out at this time," Latif wrote.

Gatti Jr. was a promising young boxer who was following in his late father's footsteps. Gatti Sr., who was one of the most beloved boxers of his era, died at the age of 39 in 2009, three years prior to being elected into the International Boxing Hall of Fame.

Gatti Sr. went 40-9 (31 via KO) during his legendary career, which included his legendary trilogy of fights against 'Irish' Micky Ward -- who was portrayed by Mark Wahlberg in the biographical film The Fighter -- from 2001 to 2003, with two of the matches receiving 'Fight of the Year' awards by The Ring magazine.

If you or someone you know is at risk of suicide please call the U.S. National Suicide Prevention Lifeline at 800-273-8255, text HOME to 741741 or go to SpeakingOfSuicide.com/resources for additional resources.