The ex-chief executive at the California Public Employees Retirement System is about to plead guilty to conspiracy.

Fred Buenrostro, who ran CalPERS for six years in the early 2000s, is expected to enter the guilty plea next week in connection with a bribery scandal going back five years.  

His lawyer tells the Sacramento Bee that Buenrostro will cooperate with the government's prosecution of Nevada businessman Alfred Villalobos.

Prosecutors claim Buenrostro conspired with Villalobos to get millions of dollars in middleman fees after Villalobos' company set up investment deals.  

Up to this point the 64-year-old Buenrostro has insisted he's done nothing wrong.

He reportedly will agree to a five-year prison term in addition to giving up what he knows.