A California elementary school suspended a 5-year-old kindergartner after he joked that he had a bomb in his backpack, his family said.

KCRA in Sacramento reported that Jackson Riley, of Modesto, was in his third week of school at Great Valley Academy, a public charter school, on Aug. 31 when he refused to take his backpack off. He told his teacher he couldn't take his backpack off because a bomb inside the bag would explode if he did.

When the teacher asked to look inside the bag, she found nothing dangerous, the news station reported.

Jackson still received a one-day suspension, his father, Ian Riley, said. The letter his parents received stated the boy had “intentionally engaged in harassment, threats or intimidation.”

"We said, 'This doesn't fit, and furthermore, we don't really feel like our son was threatening you," Riley told KCRA. "He's got an imagination. In his mind, he's being this hero that's preventing you from being exploded from man imaginary bomb in his backpack."

The Modesto Bee reported that the school told the Rileys that the code violation best fit what Jackson had done. When the family pointed out that the code applied only to students in grades four through 12, they received a second letter.

The new letter changed the violation Jackson was accused of to making “terroristic threats,” the Bee reported.

"My son never made a threat, never wanted to blow up the school," Riley told the newspaper.

Riley and his wife, Michelle, had a talk with their son about what is proper to say at school and what isn’t, and told him to follow his teacher’s rules -- including taking his backpack off when told to do so.

The suspension didn’t phase Jackson, his parents said. The next day, he was outside picking flowers to bring to his teacher.

His parents remain upset, however, because they’ve been told that the suspension will remain on their son’s permanent record. They are meeting with school officials on Friday to see if it can be resolved.

Great Valley Academy officials declined to comment on the incident, stating only that the school takes student safety and discipline seriously, the Bee reported.