Surveillance cameras at North Marion High School caught two burglars who stole the school's safe and the more than $4,000 in cash and checks inside it.
"We can put it behind 10 locked doors. If somebody is determined to get to it, they'll get to it regardless," said Kevin Christian of Marion County Schools.
Once the burglars had the safe, they no longer needed the cart, so they pitched it into a cow pasture, officials said.
The Sheriff's Office hopes there may be witnesses who didn't realize it was a crime in progress.
"They were driving and they saw two guys and thought, 'What are they
The last sign of trouble at the school was in September when two students were accused of bringing a shotgun to school, which they planned to use for a robbery.
Detectives suspect students may be responsible in the safe theft.
"Most of the time when things like this happen on campus, kids talk. Kids tell each other what they've done and word gets back," said Christian.
Anyone with information is asked to contact police.