Shotputter Inderjeet Singh on Tuesday became the second Indian athlete to fail a drugs test in recent days, embroiling the nation's Olympic squad in a doping scandal before next month's Rio Games.
The Asian champion claimed he was the victim of a conspiracy for criticising sports authorities after his A sample taken during routine testing was found to contain a banned substance.
"I am being targeted and it's a clear case of conspiracy against me. My sample has been tampered with," Singh, a gold medal winner at the Asian Athletics Championships last year, said in a statement.
"Why would I take something which is not good for health?"
"I have been framed because I am outspoken," the 28-year-old also told Indian TV stations.
An Indian sports official said shotputter Singh tested positive for the banned steroid Androsterone during out-of-competition testing by the National Anti-Doping Agency (NADA) on June 22.
"NADA has informed Inderjeet about the result. If he wants to test his B sample then it has to be done within seven days," said the official, who was speaking on condition of anonymity.
The positive test comes after revelations that Rio-bound wrestler Narsingh Yadav, a Commonwealth Games gold medallist in the 74-kilogram freestyle category, also failed a drugs test.
India has not yet decided the fate of either athlete. Yadav also cried foul, claiming his water and food supplements were contaminated with a banned steroid.
The country is about to send its largest ever Olympic squad of more than 100 athletes in hopes of improving its poor medal count.
The Rio Games are set to start on August 5 with controversy raging over the International Olympic Committee's decision not to impose a blanket ban to Russia, accused of state-sponsored doping.
India has been rocked by previous drugs scandals and is ranked third on a global list of doping offenders compiled by the World Anti-Doping Agency, behind Russia and Italy.
In 2011 six top Indian women runners tested positive for banned steroids.