A former 400-meter world champion has become the second Commonwealth Games athlete to fail a doping test in Glasgow.

Amantle Montsho of Botswana tested positive for the banned stimulant methylhexaneamine after surrendering her Commonwealth title on Tuesday by coming fourth in the women’s 400-meter final.

The Commonwealth Games Federation announced that Montsho had been suspended at a hearing on Saturday in Glasgow. Montsho requested that her backup sample be tested, which will happen on Monday in London.

The 31-year-old Montsho won her world title in 2011 but had to settle for silver at last year’s championships in Moscow. She finished fourth in the final at the 2012 London Olympics.

The CGF announcement came a day after 16-year-old weightlifter Chika Amalaha was stripped of her gold medal after a doping hearing.

The Nigerian tested positive for diuretics and masking agents after winning the 53-kilogram (117-pound) division last Friday, becoming the youngest female to win a weightlifting title at a Commonwealth Games.

There were four failed doping tests at the games four years ago in New Delhi.