Former middleweight world champion Jorge "Locomotora" Castro died at age 59 on Wednesday after collapsing at the Morón Bingo Hall in Argentina.
The police report confirmed that he suffered a drop in insulin levels caused by his diabetic condition. He received medical attention after 911 was called, but he died at the scene.
His daughter, Quimey Castro, said she was with him at the bingo hall when the medics attended to him as he died while receiving CPR.
The Morón Prosecutor's Office No. 8 is investigating the incident to determine the cause of death.
Castro had one of the most spectacular careers in Argentine boxing, with a professional record of 144 fights, including 130 wins (90 by knockout), 11 losses, and three draws.
Born in Caleta Olivia, Santa Cruz, on Aug. 18, 1967, the boxer reached the pinnacle of the sport in Aug. 12, 1994, when he won the vacant WBA middleweight world title against Reggie Johnson in Buenos Aires.
His greatest moment on the international stage came in Dec. 10, 1994, in Monterrey, Mexico.
On that day, "Locomotora" Castro defended his WBA title against John David Jackson in what was The Ring's Fight of the Year.
The fight started poorly for Castro, who endured continuous punishment that caused swelling around both eyes and left him on the verge of being knocked out.
However, in the ninth round, he landed a powerful left hook to his Jackson's chin that knocked him down.
After two more knockdowns, the fight ended by knockout.
In recent years, the former world champion distinguished himself through his charitable work at soup kitchens and community centers in the Buenos Aires area, especially in Lomas de Zamora and Morón.
ESPN's Carlos Irusta contributed to this report.