CHICAGO (CBS) — Police in Harvard, Ill., have arrested a student they say left a used shell casing in an elementary school on Monday–and on Wednesday left more spent casings at another school and on a school bus.

Harvard police say the boy is 12 years old and is a student at Harvard Junior High.

Apparently all he wanted to do was impress his friends.

On Monday, a used shell casing from a .22 was found in the Crosby Elementary cafeteria.

And now police say the boy had three .30 caliber spent shell casings to bring to the junior high.

Harvard Police Chief Dan Kazy-Garey says the boy lost one on the bus and then “realized the consequences of his actions” and dropped the other two in a school restroom.

Police say all schools in Harvard were on lockdown while police investigated.

The 12-year-old is charged with disorderly conduct and was released to a parent.

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