Following the quarterfinal match in the bantamweight division where Conlan left his opponent Vladimir Nikitin of Russian Federation bloodied and bruised, the judges ruled that Nikitin would advance much to the chagrin of Conlan.
It comes just one day after Ireland's Michael Conlan was defeated by Vladimir Nikitin by unanimous decision, despite seemingly out-boxing his Russian opponent throughout the fight.
Conlan, who had been the last Irish boxer left in the tournament, lost 28-29 on all three scorecards.
Olympic boxing's governing body AIBA has announced that it has expelled a "handful" of referees and judges involved in controversial decisions during the Rio Games.
Moments after the defeat, Conlan fumed: "AIBA cheats, they're f**king cheats". I don't give a f**k for cursing on TV. "My dream's been shattered now", said Conlan, who won bronze in flyweight at the 2012 London Games. "You saw by his reaction that he knew he didn't win". "One thing for sure is I will not box in an AIBA competition again as they are rotten to the core".
"Hey Vlad. How much did they charge you bro?", he asked.
"AIBA will never say they were corrupt, they will say they weren't happy with their performance", said a highly placed source. "We're in a transition period and we have a job to do with our coaches to train their boxers towards the criteria which AIBA is looking for", he said. I would advise anybody not to compete for AIBA. They're f***ing cheats. Sorry about that, but that's me.
"We have a lot of educating to do and a lot of evaluating to do", Aiba official Tom Virgets told the BBC.
According to Comubox data, Conlan threw more punches than the Russian - 365 against 257.
Continuing on from criticism of the previous night's decision to award another Russian - super-heavyweight Evgeny Tischenko - the gold medal over Vassiliy Levit, some of the sport's biggest names let fly.
The five ringside judges for Conlan's bout - from which three scores are randomly chosen - hailed from Brazil, Canada, Sri Lanka, Vietnam and Poland respectively.
The American boxer looks set to progress to the gold medal bout against either Robeisy Ramirez Carrazana of Cuba or Uzbekistan's Murodjon Akhmadaliev tomorrow evening.