(Reuters) – Colombian 400 meters runner Diego Palomeque Echevarria was excluded from the London Olympics on Sunday after a second sample tested positive for testosterone, the International Olympic Committee said.

Palomeque had been provisionally suspended on August 4 pending results of the second test. He now faces a maximum two-year ban as a first-time offender.

“Eighteen-year-old Palomeque Echevarria, who was scheduled to compete on 4 August, provided a urine sample on 26 July in London that tested positive for testosterone of exogenous origin,” the IOC said.

“The analysis of the B sample confirmed the results of the A sample.”

Palomeque is the 12th athlete to be sent home by the IOC or the team itself for failing a drugs test since the start of the Olympic period on July 16.

The IOC has conducted more than 5,000 tests at the Games that end later on Sunday.

More than 115 athletes were also caught using banned substances in the three months leading up to the Games following increased testing by national and international anti-doping agencies, designed to root out cheats before they arrived in London.