Everywhere House by Jane Meyerding

It's the late 70s in the university town of Seattle, Washington. The
brutal stabbing of a philosophy professor implicates Barb, an angry member
of the ultra-radical lesbian collective, the Furies. Student Terry Barber,
drawn to Barb's plight when other community women shy away, fears that
Barb will not receive fair treatment by the authorities. She begins her own
investigation into the death, uncovering Barb's secret identity, a sinister
religious cult, and growing political and personal struggles within her own
lesbian collective, Everywhere House.