OKLAHOMA CITY - Copper thieves go on a spring break heist, stealing from three Oklahoma City Public schools; the schools' AC units, stripped bare.

More than $750,000-worth of copper was taken. Police say thieves broke into the schools' fenced area where the AC chillers are stored and stole the copper. Only scraps of aluminum were left on the chiller units, where copper coils once surrounded.

"We have more than 70 buildings spread across Oklahoma, so we're always a target," says Tierney Tinnin, spokesperson for Oklahoma City Public Schools. "That's why we need the community to help keep a lookout."

And of all the district's schools, Tinnin says the majority of them have had copper thefts in the past. This time, Copper thieves targeted Classen School of Advanced Studies, F.D. Moon Academy and Oklahoma Centennial Mid-High School.

Police believe the copper was stolen between 11:30 p.m. and 12:30 a.m. from March 13 to March 18. They believe a suspect broke the lock and chain securing the chiller in order to take the copper and sell it to a metal recycling center.

"It's unfortunate that we've been dealing with copper thefts for this many years, but it continues to be a problem as the price of copper tends to stay somewhat high," says MSgt. Gary Knight of the Oklahoma City Police Dept.

Knight says copper theft is a hard crime to try to prevent beforehand since any place with an air conditioning unit can be a target. Conveniently, all three schools have a backup chiller, so they won't be without air conditioning. And all three sites were set to receive new units this year as well.

"We're getting them replaced anyway, so it's not going to be a financial cost to us," Tinnin says. "It's really just frustrating when you've got thieves who come in and take advantage of a school and the children who go to that school."

The schools say they've tried different ways to secure the chiller units, but say thieves will go to extreme lengths to steal copper. They say the community's watchful eye is the best way to help prevent this crime.

"We're not immune to this problem like any other business," Tinnin says. "It's just the fact that these are kids who walk into these buildings each and every day and are the future of our city, and we want the thieves to really think about that."

Police don't have any suspects yet, but they do have surveillance video for one of the schools. If you know anything about the theft, call Crime Stoppers at (405) 235-7300.