The Bulgarian Helsinki Committee presents a series of highlights from its 2014 Annual Report on Human Rights in Bulgaria. You could find more details here.
The many problems with the Bulgarian prison system weren't overcome in 2014. Violence by officers against inmates, overcrowding and outdated prison facilities were some of the issues detailed in the 2014 annual report on Bulgaria, which is more critical than reports by the Committee against Torture of the Council of Europe.
In Sofia Central Prison alone, two recent cases of prisoner abuse by guards gained publicity. In one of the cases, several officers severely beat inmates even though they were not resisting officers' commands. One of the victims needed to be taken by wheelchair to the prison hospital for treatment. After seeing him, the doctor expressed his indignation at the guards with the words "Shame on you!"