ANDERSON, Ind. — A 14-year-old boy was expelled from school and detained at a local juvenile detention center for reportedly bringing weapons onto a school bus in early October.

Acting on a tip received from a parent, a middle school principal used a metal-detecting wand to check each student on the suspect’s bus as they exited. The boy with the gun reportedly passed it to students behind him when he noticed the screening, and it ended up in a trash bin.

After all the students passed the inspection, authorities boarded the bus and found the .22-caliber gun as well as a small knife hidden under one of the seats.

With the information provided by the tip, investigators connected the weapons with the 14-year-old boy. A student had told a parent that the teen had previously brought the weapon to school and was planning to bring it back that day.

Authorities said that although the gun was unloaded, it could have caused much more trouble on the bus than it did.

“Anything could have happened,” Anderson Police Sgt. William Casey told reporters. “we’ve got a kid with a gun — he could have pointed it at somebody. He could have caused some chain reaction where somebody could have reacted in a violent way to protect themselves.”

In addition to being expelled from school for the rest of year, authorities said the teen would be charged with a class-D felony. Three other students who passed the gun around on the bus were suspended for three days.

The 14-year-old told authorities that he bought the handgun from another boy for $10. The other boy, an 11-year-old, reportedly found the pistol in a bush at a city park while playing basketball. Investigators said they hoped to determine the origin of the gun by tracing its serial number.