In an apparent case of first impression, prosecutors in the pending Catholic Archdiocese of Philadelphia sex-abuse case want to present expert testimony on the process sexual abusers of children undertake to “‘groom’” their victims.

No Pennsylvania appellate court has addressed the issue of expert testimony on this phenomenon, prosecutors Patrick J. Blessington, chief of the special investigations unit, and Anthony V. Pomeranz, an assistant district attorney in the appeals unit, wrote in their motion in limine to permit a judicial instruction on such expert testimony.