Electronic and paper files were seized from McHenry County State's Attorney Louis Bianchi's office Friday afternoon as a search warrant was executed.
McHenry County Undersheriff Andrew Zinke confirmed that sheriff's department officials were asked by special prosecutor Henry Tonigan III to stand by Bianchi's office as a search took place around 4 p.m.
Tonigan, a retired Lake County judge, was appointed last September to investigate claims made by Bianchi's former personal secretary that she was required to do political work for him during business hours.
Amy Dalby, 25, of Woodstock, said she was required to type letters to campaign supporters, keep a political donor list and set up a fundraiser.
Zinke said Tonigan "brought in his own people to conduct the search." Bianchi was not present, he said.
Zinke declined to comment further.
Bianchi, a second-term Republican from Crystal Lake, repeatedly has denied campaigning out of his county office.
When McHenry County Judge Gordon Graham appointed Tonigan to look into the claims, Bianchi said he welcomed the investigation.
Tonigan conducted an investigation for several months before empaneling a grand jury this spring.
The grand jury has met on multiple occasions, and is believed to have taken testimony in recent weeks.
Bianchi has yet to return calls from the Daily Herald seeking comment.