This Indiana teacher really blew it.

Samantha Cox, 24, faces drug-related charges after being caught on camera by her students Wednesday allegedly snorting a mixture of cocaine and heroin in her classroom, CBS Chicago reported.

“She tried to hide herself,” said John Rogers, a student who claimed he recorded the cellphone video. “She wasn’t at her desk where we could see her. She was all the way in the corner where she thought we can’t see her.”

Video footage shows the English teacher sitting in a corner of her classroom and making lines out of a white substance on a book atop her lap — before getting up and hunching over it, apparently snorting the powder.

School administrators alerted St. John police, who arrested Cox for possession of a controlled substance and possession of drug paraphernalia.

Cops praised the sleuthing students, saying their actions “showed a tremendous amount of fortitude and integrity.”

In robocalls to parents, Lake Central Superintendent Larry Veracco said police and school staff took “swift and forceful action.”

“[Safety] remains the top priority of our school staff,” he said.