TONGANOXIE, Kan. -- School officials aren't saying why a 9-year-old brought a CO2 gun to school this week, but the episode prompted them to send the boy home and a letter was sent to parents who have kids at the school.

The boy brought the gun to Tonganoxie Elementary earlier this week.

The Leavenworth County Attorney said the gun was not loaded and there will be no criminal charges will be filed because of the boy's age. But the child does face suspension or even expulsion.

The attorney's office said any child under 10 years can't be charged with a criminal offense. The courts, however, will consider a Child in Need petition, which looks at the child's welfare and if there are any problems at home.

Jennifer Boone has a 7-year-old at the school. She said she was surprised to receive a note from the district saying that a weapon had been found on school grounds.

"It was most likely harmless, but you never know," Boone said. "He probably wanted to show it to his friends. But how he got out of the house with it is a little concerning."

Boone said the letter indicated that the air gun was in the boy's backpack. It said that the gun was removed before the start of the school day.

The school district superintendent did not return KCTV5's calls concerning the air gun.