A man accused of breaking into a home on New York's Long Island and fatally stabbing the wife of a former U.S. ambassador now faces a first-degree murder charge.

A grand jury on Wednesday returned the upgraded murder charge against Robert Schiavo in the March 8 death of Nancy McKinley during a break-in. He has pleaded not guilty and is being held without bail.

The 22-year-old Medford man originally was charged with second-degree murder and burglary. Prosecutors say the upgrade reflects that the killing took place during another felony.

Schiavo's attorney says his client had no criminal history. If convicted, Schiavo faces life without parole.

The 61-year-old McKinley was the wife of former U.S. ambassador Brunson McKinley.