Career
He is of Turkish ethnicity. Demirev tested positive for a steroid in 2008 during an out-of-competition test, along with ten other weightlifters and therefore Bulgaria"s weightlifting federation withdrew its team from the 2008 Summer Olympics in Beijing, China. Apart from Demirev the athletes who tested positive were Ivailo Filev, Alan Tsagaev, Mehmed Fikretov, Ivan Stoitsov, Ivan Markov, Georgi Markov, Velichko Cholakov, Milka Maneva, Donka Mincheva and Gergana Kirilova.