Rosario DiGirolamo surrendered to Delaware state police immediately after his return from Italy. He was booked and released.

New Jersey authorities describe DiGirolamo as a "person of interest" in the disappearance of his girlfriend, Amy Giordano of Hightstown. The Mercer County Prosecutor's Office said investigators who went to Delaware were not able to question DiGirolamo, The Times of Trenton reported.

DiGirolamo flew to Italy in mid-June, a few days after a nurse found his son, Michael. The boy, now 1 year old, had a note purportedly written by his mother pinned to his diaper that said his name was John Vincent.

Giordano was last seen at a local supermarket June 7. She and the married DiGirolamo met four years ago when she was living near a pizza parlor where he worked in Brooklyn.