Investigators say the boys set up thirteen soda bottle bombs in the parking lot of the Church of Jesus Christ of Latter Day Saints near Meritus Medical Center.
A nearby resident called 911 after hearing several explosions Saturday.
The Washington County Sheriff's Office and the Hagerstown Fire Marshal's Office responded to the scene and determined three of the thirteen devices had not exploded and quickly notified the Office of the State Fire Marshal Bomb Squad.
The three unexploded devices were rendered safe and the evidence was collected for further evaluation, according to the fire marshal's office.
The boys told authorities they learned how to build the "bombs" on the internet.
No one was hurt and no property was damaged.
The boys have been referred to an organized referral program to address the seriousness of their actions, the fire marshal said.
"The construction of these types of devices in this and similar incidents have sometimes been misrepresented as fun. However, the seriousness and destructive nature of these devices can cause: loss of vision, respiratory distress, loss of extremities and possibly death," stated State Fire Marshal William E. Barnard.