At least that is what maverick Russian news agency Regnum reports http://www.regnum.ru/news/1018257.html (in Russian). In a special report, published Monday 23 June the agency publishes letters of terrorist suspects that were arrested after the attack in October 2005 in Nalchik, Kabardin-Balkaria.
The author of the letter describes the horrible ways in which he was treated in the police department, including electric shock, death squads, sexual violence, beatings, etc. These facts have been collected and filed in the European Court of Human Rights in Strasbourg. Number of the described characters died either while in detention or immediately after their release. Russian prosecutors found no evidence of exessive application of force.