A U.S. senator urged the State Department on Monday to deny entry to the United States for all Russian officials allegedly responsible for the prison death of a lawyer.

Sergey Magnitsky died in November after spending almost a year in jail. He was awaiting trial on tax-evasion charges linked to his work with a British investor barred from Russia because of allegations he was a security risk.

Sen. Benjamin Cardin, D-Md., released a letter he wrote to Secretary of State Hillary Rodham Clinton asking her to deny entry to the United States of several senior officials from the Russian Interior Ministry, the Federal Security Service and the Federal Tax Service.

Magnitsky's colleagues and attorney believe the public officials listed by Cardin were involved in the lawyer's death.

"We can take the concrete action to ensure those public officials and others who share responsibility for this crime should be denied entry visas to the United States," Cardin wrote. "Since the death, a number of prison officials have been fired, but no one has been prosecuted for his torture or death, nor for participating in the corruption he exposed."