THE BRONX - A man made a startling discovery while walking his dog Thursday.

Daniel Santiago says he found what he believes is a human skull.

He says his dog started sniffing around a plastic bag and when he opened it up he saw the skull, which appeared to be missing its jaw bone.

Santiago called his friend Daqwaun Ralls to take a look at it before handing it over to the NYPD to figure out where it came from.                         

The NYPD says since the skull was found near the garbage behind a school, it could just be a prop from one of the science labs.

The medical examiner is investigating.