A Russian prison official reportedly admitted Thursday that harsh prison conditions are partially to blame for the death last week of a lawyer being held in a Moscow detention center.
Lawyer Sergei Magnitsky was arrested in November 2008 on tax-evasion charges linked to his work with a British investor barred from Russia as an alleged security risk.
Magnitsky's lawyers said he died last week after being denied medical assistance for pancreatitis while in pretrial detention at Moscow's Butyrskaya jail.
A deputy head of the Federal Penitentiary Service said there had been "visible violations on our part" at Butyrskaya, according to the ITAR-Tass and RIA-Novosti news agencies.
"We are not going to minimize our guilt in any way _ it is definitely there," Alexander Smirnov was quoted as saying.
President Dmitry Medvedev has ordered an investigation into Magnitsky's death.
Interior Ministry investigators said Wednesday they had known nothing of Magnitsky's health problems, and said he had died of heart failure.
Magnitsky was involved in defending Hermitage Capital Management and its partner HSBC against a multimillion-dollar fraud and forgery scheme involving Interior Ministry officers. Hermitage CEO William Browder said the scheme involved illegally taking over assets and using them to fraudulently reclaim $230 million in taxes from the state.
Browder said Magnitsky was arrested by the same Interior Ministry officers implicated in the alleged fraud.
After Magnitsky's death, Browder made public one of his letters describing harrowing prison conditions and expressing frustration at being unable to see his mother and wife or to speak to his two children during nearly a year behind bars.
The American Chamber of Commerce in Russia sent a letter to Medvedev on Wednesday expressing support for his order and calling for a "fair and transparent investigation" into Magnitsky's death.