The Racine County sheriff's office identifies the man as 37-year-old Rajko Utvic.
The sheriff's office says two Racine police officers responded to a 911 call on Sunday and found Utvic armed with a knife. Authorities say Utvic refused orders to drop the knife and advanced on the officers. He was shot and killed by one of the officers.
The names of the officers were not released. The sheriff's office will investigate the shooting and forward its findings to the district attorney's office.