American weightlifter Norik Vardanian has tested positive for a banned substance in a sample he gave while competing for Armenia at London 2012.
The 29-year-old finished 11th in the -94kg class for Armenia, where he was born, but has since switched to represent the United States.
A retest of his 2012 sample revealed the presence of a steroid.
A total of 43 weightlifters have now failed retests from the 2008 and 2012 Olympic Games.
Six more competitors from Vardanian's event at the London Olympics are already facing disqualification after retests found steroids.
Vardanian was previously banned for six months in 2009 after testing positive for cannabis.