ORANGE PARK, Fla. -

Plantation Oaks Elementary School in Orange Park has been vandalized twice in a week, and now investigators are trying to figure out who's responsible.

Seven fifth-grade portable classrooms were damaged overnight Sunday into Monday. Nothing was stolen, but the telecommunication lines were ripped out of some of the classrooms, and windows were broken in all seven of them.

Students were kept out of the areas Monday morning until the glass was cleaned up.

The second-grade hallway had windows broken and the fire extinguishers were expelled both in the hallways and in the cafeteria. The kids there also had to be kept away until the cleanup was completed.

Clay County deputies estimate about $6,000 in damage.

The school was vandalized once before last week, with 11 portable classrooms damaged, as was Oakleaf Junior High School, where fire extinguisher foam was sprayed throughout the gymnasium.

Investigators are trying to figure out if the crimes are related. They said there is a common theme.

"Once the suspects enter the school, they break in and steal fire extinguishers," Detective Mark Romano said. "They are discharging fire extinguishers in various parts of the school."

Deputies believe teenagers are responsible for the crimes.

"The extent of the damage done leads me to believe it's more than one person," Romano said.

"It's the end of the year, and definitely that's not an excuse, but it's the end of the year and kids start getting antsy and doing dumb things," parent Latoshia Hall said. "Hopefully the students aren't doing it because the repercussions are heavy."

Deputies are stepping up patrols in the Oakleaf area at night.

"I think it's kids trying to be rebellious and stuff and making bad decisions, just being crazy," student Vianka Brackins said.

In all three cases, the damage is estimated to be more than $10,000. 

"If you could please tell your teacher or administrator if you know someone who might have done it or said something, tell them in confidence," Romano said.

Anyone with any information about the vandalism is asked to call the Clay County Sheriff's Office at 904-264-6512 or Crime Stoppers at 866-845-TIPS.