HOUSTON (KIAH) — The Houston Independent School District is having to rely on “substitute vehicles” to cover 14 routes to and home from schools after thieves stole the catalytic converters from at least 12 buses.

The thefts happened sometime during the Thanksgiving break at HISD’s Northwest Motor Pool at 6351 Pinemont Drive.

It’s unclear how long the buses will be out commission or how much it will cost the district to return them to its fleet.

“HISD transportation vehicles are insured,” the district replied when emailed questions about the theft. “We are currently assessing costs and best course of action for repairs.”

What is also unclear is how the thieves were able to pull off the crime.

The bus barn lacks surveillance, but it does have a tall fence topped by barbed wire, and the gates have locks.

The district also took an extra precautionary step in hopes of preventing catalytic converter thefts from the buses in question, but it was unsuccessful.

“The affected buses had protection plates installed as a deterrent,” the district said in another email.

The Houston Police Department’s Auto Theft Division says a similar measure — installing steel rebar cages around catalytic converters — helped cut down on thefts at a local UHaul franchise.

“There were still a few that got cut off,” Sgt. Tracy Hicks said. “They used a cutting wheel to cut the cages around them, but it sure did slow them down, and it actually reduced their thefts quite a bit.”

Thieves steal catalytic converters because of the valuable metals inside of them.

Hicks says the price of those metals has declined significantly in recent months, and that’s led to a dip in thefts.

But he still urges everyone to take precautions to protect their catalytic converters.

“We can’t let our guard down,” Hicks said. “We can’t make it easier for (thieves). So prevention is still huge.”