The Portugal-born man, who trains at Shannon's gym in Openshaw, returned a second positive test for nandrolone - plus an amphetamine.
He will now almost certainly be stripped of his World Boxing Union middleweight title and could even face a life ban from the sport.
But Monteiro, 34, who beat Failsworth's Anthony Farnell in 10 rounds last month, said: "I'm not a drug taker."
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S.Gibbons, Trafford, Manchester (03/03/2005 at 18:43)
he hasn't been stripped of the title yet as his case hasn't been heard - the BBBoC and Kings College London know for a fact that he has the proof his results were altered in his posetion so they wont give him a chance to show them up.
Boxing is the most corrupt sport and he knows who is behind his injustice - as probably does most of the boxing world.