WISC-TV reports authorities searched along Highway 14 east of Black Earth Thursday afternoon and planned to renew that effort Friday.
A family member found 43-year-old Cheryl Gilberg fatally shot at her home in the Village of Mazomanie Sunday evening.
The medical examiner ruled the death a homicide.
Authorities have named a Janesville man as a person of interest.
The 39-year-old man is being held in the Rock County Jail on unrelated charges.