LAWRENCE, Mass. (CNN, WCVB) - Police in Lawrence, Massachusetts are investigating an unusual case. A woman says she found a bullet inside a jar of peanut butter.

Police were called to the School for Exceptional Studies, housed in the old Lawrence High School, on Monday when a teacher's aide opened a new jar of peanut butter and found a .45 caliber bullet inside.

"The teacher's aide when she opened the peanut butter, she had to break the seal. My understanding is in her opinion it looked normal. I don't how it was that that wound up in that jar. Where it came from, how it got there. Nobody can explain it, and neither can I because the jar was sealed," says Yenny Ferrerras.

Ferrerras says she bought the jar of peanut butter, manufactured in Everett, two weeks ago. She gave it to her disabled daughter to take to school, so she and her classmates could have snacks.

The investigation is wide open. There have been no judgments made at this point.