The arrest of a sexual predator at the Westchester County Homeless Shelter in Valhalla has neighbors upset. Jayson Rivera, 28, is a level three-sex offender on parole after spending time in jail for fondling a 6-year-old girl in Mount Vernon. Two days after moving into the shelter, Rivera was charged with lewdness. Police say he exposed himself to a female worker at the county-owned facility. For those who work and live near the shelter, the arrest has reignited their safety concerns. Ned McCormack, the leader of a neighboring homeowners association, thinks the county made the wrong decision in December when it moved the shelter from the county airport to the Grasslands Campus near the children's hospital.