SEGUIN, Texas -

Three teens are in custody after breaking  in and vandalizing a historic building in Seguin.

It happened Monday at the historic Juan Seguin Campus.

Police said a witness reported seeing the teens walk into the abandoned school.

"Officers arrived on the scene. One went to the back door, another went to the front," said Seguin police Sgt. James Springer. "We searched the building and found where they had attempted to start small fires."

Three teens -- a 12-year-old, a 14-year-old and 15-year-old -- were detained, charged with burglary of a building and taken to juvenile detention.

One of them was also charged with possession of synthetic marijuana.

Springer said all three were already on probation.

Seguin ISD spokesman Sean Hoffmann said that the Juan Seguin Campus is a historic building with deep roots in the community and, although it's been closed for three years, vandals are finding a way to get in.

"Essentially, it's been vacant during that time, but only recently we've had teens breaking windows, hanging out inside," said Hoffmann.

Hoffmann said since Sunday night, there have been four break-ins at the campus.

Two of them happening after Monday's arrest.

"It's kind of a sad state of affairs when you have school-age kids coming in, breaking  into schools and vandalizing schools," said Hoffmann.

Hoffman said because the break-ins have been happening more frequently, the school district is having to take more steps to secure the building.

"We're boarding up windows," he said. "We've got a lot of windows on this campus. We have city crews installing lights, cutting back bushes and shrubs that are overgrown. We're having to invest in doing some work right now."

For a list of recent stories Stephanie Serna has done, click here.