SHANGHAI -- Olympic champion Cesar Cielo is expected to find out by Friday whether he will be banned from swimming, after the Court of Arbitration for Sport held a special six-hour hearing Wednesday into the Brazilian's doping case.
The CAS panel was specially assembled to deliver a verdict in the case before Cielo is scheduled to compete in the freestyle relay Sunday at the swimming world championships.
Cielo is hoping to defend his world titles in the 50- and 100-meter freestyle. He is also entered in the 50-meter butterfly.
FINA, swimming's governing body, challenged a Brazilian federation decision to give Cielo only a warning after he tested positive for furosemide, a banned diuretic and masking agent, at a meet in Rio de Janeiro in May.
Cielo said he consumed the drug in a contaminated batch of a food supplement he regularly used. He could face a ban of two years under WADA rules.
Three other Brazilian swimmers -- Nicholas Santos, Henrique Barbosa and Vinicius Waked -- also tested positive for furosemide and were let off with warnings by their national federation. Waked previously served a two-month ban for a separate doping offense.
All four swimmers attended the hearing Wednesday at the Shanghai University of Political Science and Law, although only Cielo has qualified to compete at worlds.
Cielo was represented at the hearing by Los Angeles attorney Howard Jacobs; FINA flew in from Switzerland its lawyer specializing in doping cases, Jean-Pierre Morand.
Jacobs previously represented American swimmer Jessica Hardy in a similar case: Hardy withdrew from the U.S. team ahead of the 2008 Beijing Games and later was ordered to serve a one-year ban, even though the CAS accepted that she was not at fault for a contaminated dietary supplement.
"I can see when there is real doping and this is not, for sure," said Sandre Soldao of the Brazilian anti-doping agency, a former Olympic triathlete who attended the hearing. "There is a problem in the supplements industry. Everyone in sports medicine knows about this -- 30 percent of supplements are contaminated with something and that's a real problem.
"All athletes use supplements these days. For me it's very clear."
The Brazilian anti-doping agency sends all of its samples to a Montreal lab for testing, and that's where the positive tests were first reported, according to Soldao. The Brazilian lab then tested the supplements provided by the athletes and found traces of furosemide, according to Soldao.
FINA executive director Cornel Marculescu said recently that athletes are responsible for any supplements they consume, and said FINA appealed because there was "missing information" in the case.
Cielo swept the signature sprinting events -- the 50- and 100-meter freestyle -- at the last worlds in Rome two years ago. He also took gold in the 50 free at the 2008 Beijing Olympics.
If Cielo is banned for more than six months, the Brazilian could be excluded from defending his Olympic title at the 2012 London Games under existing International Olympic Committee rules.
Some witnesses testified via video conference during the hearing.
"There were a lot of witnesses," Jacobs said. "I would rather not get into the specifics. We're going to let the arbitrators reach their decision and we'll have that by tomorrow or the next day."
The CAS panel was composed of Allan Sullivan of Australia, Oliver Carrard of Switzerland and Jeffrey Benz of the United States.