Beloit police told Racine authorities that the 20-year-old Beloit man may have fled to Racine.
After monitoring the home, authorities saw the suspect leave in a vehicle around 10 p.m. Wednesday and arrested him without incident on Interstate 94.
The man is being held on a warrant for first-degree intentional homicide.
He is one of two men wanted in the killing last Friday of 20-year-old Raymond Holloway of Beloit.
The other suspect, a 31-year-old Beloit man, remains at large.
Holloway was the second man shot to death in Beloit that day.
Officers earlier found 36-year-old Edward Haley lying in the road with gunshot wounds.
Police are investigating whether the two homicides are related.