A detainee at the Cook County Jail has been charged with threatening his public defender.

About 11 a.m. Wednesday, Michael Roberson, 34, threatened his assistant public defender with physical harm in a courtroom lockup at the Leighton Criminal Court Building, 2650 S. California, according to the Cook County Sheriff’s Office. He was charged with threatening a public official, a felony.

Roberson was being held at the jail in connection with a 2013 aggravated criminal sexual assault case, the sheriff’s office said.