The Los Angeles Times said several current and former prosecutors had been subpoenaed recently to answer questions about charges from critics that Rackauckas had granted favorable treatment to his political allies and campaign contributors in a number of unspecified cases.
"I have received a subpoena, and I have cooperated fully," Christopher Evans, a former top aide to Rackauckas, told the newspaper. "I was admonished not to discuss the questions and answers."
Evans did tell the Times that he had been questioned by the grand jury's criminal justice committee, which monitors the efficiency of county law enforcement and the courts. Grand jury testimony by law is secret.
Rackauckas is in the midst of a re-election campaign against prosecutor Wally Wade, who was endorsed last month by a number of fellow prosecutors. A spokesman for Rackauckas' campaign accused Wade of mischaracterizing the investigation in order to "feed his negative campaign."
Rackauckas himself had no immediate comment on the investigation, however a supervisor in the DA's office, who asked not to be identified, told the Times that the investigation was more of a routine audit similar to the probe of the office conducted in 1997.
"We assume the office will receive a good evaluation," the source said. "This is a normal procedure."