WILMINGTON, Del., June 28 (UPI) -- An arrest warrant was issued Thursday for the father of a 1-year-old boy abandoned in a hospital parking lot in Newark, Delaware.

Rosario Digirolamo is believed to be in Italy. He flew to Milan five days after a nurse found the boy at Christiana Hospital.

Investigators initially thought the boy had been abandoned by his mother because of a note found tucked into his diapers. But Delaware State Police have discovered that Digirolamo made a call from his cell phone near the hospital on June 9, around the time the boy was discovered, The Wilmington News Journal reported.

The warrant charges Digirolamo with endangerment and abandoning a child.

The boy's mother, Amy Giordano, talked to a friend on the telephone two days before her son, Michael Digirolamo, was abandoned and has not been heard from since. The boy was identified by her landlord in Hightstown, N.J.

Rosario Digirolamo telephoned his father two days before he left for Italy. His car was found abandoned in the borough of Staten Island in New York.