COSA (Circles of Support and Accountability) have been fully implemented and accepted in the Dutch probation organization. In COSA projects, volunteers support a former sex offender during his rehabilitation, supervised by professionals. Projects offer national coverage and until now, 42 sex offenders have been supported. International effect studies and Dutch research into effective processes offer a scientific framework, offering the theoretical and empirical underpinnings for a COSA intervention model. The normative basis of COSA is found in its specific place in restorative justice. Primarily, COSA strives for restoration of relationships within a moral and responsible community and restoration of the offender. Restoration of family bonds is an option, but needs to be well coordinated with professionals.