Russia's top investigative agency has closed its probe into the death in prison of a lawyer who exposed what he said was staggering official corruption, just days before his posthumous trial is to begin.

The Investigative Committee said Tuesday that no crime was committed in the arrest and imprisonment of Sergei Magnitsky, who died from untreated pancreatitis in 2009.

A report by Russia's presidential human rights council in 2011 found that prison officials repeatedly beat Magnitsky and denied him medical treatment.

Magnitsky was arrested for tax evasion after alleging corrupt officials and organized criminals claimed a fraudulent $230 million tax rebate through stolen subsidiaries of his client. His trial is to begin Thursday, more than three years after his death.