The Investigative Committee on Wednesday refused to file charges against investigators involved in the case of Hermitage Capital lawyer Sergei Magnitsky, who died in pretrial detention after being kept there at their request.

The investigators were accused of abuse of office and accepting a bribe by human rights champion Lyudmila Alexeyeva, but the Investigative Committee said it had found no reason to open a criminal case against them after reviewing a request from Alexeyeva, Interfax reported.

Alexeyeva promised to appeal.

Meanwhile, a second medical inquiry into Magnitsky's death has reiterated that he died of sudden heart failure — a conclusion criticized by his former employers as a cover-up for the investigators who kept him in custody.

The new medical report, whose authors were not unidentified, was released Tuesday, Interfax reported.

Hermitage Capital, once Russia's biggest foreign investment fund, denounced the findings, saying in a statement Wednesday that they "do not seem trustworthy and are aimed at covering up the crimes committed against him — illegal arrest and intentional deprivation of life."

The statement said Magnitsky had been healthy before his arrest but developed numerous serious illnesses, including pancreatitis, because of poor living conditions during his year in detention.

Magnitsky's lawyer, Yelena Oreshnikova, said the report also found that her client had received insufficient medical assistance in prison, Interfax reported.

Magnitsky, 37, died in the hospital of the Matrosskaya Tishina pretrial detention center in November. He claimed that his case was revenge for his accusations that Interior Ministry officials stole $230 million in government funds.