CHICAGO (CBS) — One day after the primary election and less than a week after federal agents raided his home and office, a state house lawmaker from Elgin has resigned.

Citing health reasons, Democrat Keith Farnham has “immediately resigned” from his Elgin-based 43rd Legislative District.

READ MORE: 17-Year-Old Boy Killed, 4 Injured In Evanston Shooting

Farnham submitted a letter to the Secretary of State’s office, which was addressed to House Speaker Mike Madigan.

“It is with great regret today that I announce my resignation from the office of state representative, effective immediately,” Farnham said. “I have been battling serious health issues for a number of years and the coming months will require my full attention.”

Farnham ran unopposed in Tuesday’s primary. Democrat party leaders, led by Madigan, will appoint a replacement to run in the November election.

Last week, federal search warrants were executed at Farnham’s Elgin home and office.

Randall Samborn, a spokesman with the U.S. attorney’s office in Chicago, said last week that search warrants were executed Thursday by agents of the Immigration and Customs Enforcement’s Homeland Security Investigations as part of an “ongoing investigation.”

He would not comment on the reason for the warrants or whether anything was taken during the searches.

READ MORE: Man Loses $6,500 To Scammers And Chase Bank Wouldn't Cover Him, Until CBS 2 Stepped In

No search warrant was issued for Farnham’s Springfield office.

Elgin accountant Crain Mason’s office is right around the hallway from Farnham’s.

“I only knew him as a really nice guy who would chat with me in the hall,” said Mason.

Farnham’s resignation means Democratic leaders now have to appoint someone to fill his seat and vote on someone to take his slot on the November ballot.

Farnham ran unopposed this primary. His departure now has Elgin area Republicans poised to get back in the general election game.

“It gives us an opportunity if we can identify a candidate that has got leadership and community service,” said Elgin Township GOP Chairman David Rickert.

MORE NEWS: Woman Dead, Child Among 3 Injured After House Fire In Clearing

Republican leaders in Elgin will hold a slating meeting on April first. Some have already expressed interest in running in November – including former Elgin State Senator Steve Rauschenberger.