Belarusian shot putter received one-year ban for her positive for steroid

Nadezya Ostapchuk, a Belarusian shot putter, received the gold medal at the 2012 London Olympics. But she failed a drug test. As a result, she lost the medal that was given to Valeria Adams of New Zealand.
Two tests manifested that a steroid’s metabolites presented in her urine samples.
If a sportsperson is caught using any forbidden products, he/she is usually sentenced to a ban of two years. As for Nadezya Ostapchuk, she received one-year ban. Why was the sentence lighter? There were certain circumstances that proved the following aspect: the shop putter didn’t apply any prohibited medication intentionally.
At the beginning the shot putter blamed his former coach. She confirmed that he had sabotaged her sample.
The Belarusian National Anti-Doping Agency examined this case. The International Association of Athletic Federation assisted the investigation. It was determined that Yefimov was guilty. This person put powder of methenolone into food of the Belarusian shot putter during the last week before the 2012 Olympic Games. The coach claimed that he had worried about Nadezya Ostapchuk. He believed that this steroid would help to win.
In fact, it is difficult to determine why Yefimov has done it. He only caused the trouble.
Anti-doping officials accepted these affirmations. That’s why the Belarusian shot putter received just one-year ban.
As for supporters of Valeria Adams, they didn’t believe that the Belarusian shot putter had not administered the steroid knowingly. They claimed that Yefimov just put efforts to protect Nadezya Ostapchuk. They confirmed that Nadezya Ostapchuk had taken steroids under recommendations of her coach.
If the Belarusian shot putter’s performance was great certain months before the 2012 Summer Olympics, her trainer had to be sure that she would win. Why did he trouble about?