Raw video: US school teacher filmed 'snorting cocaine' by students in classroom

A US high school teacher has been arrested after students filmed her appearing to prepare and then take cocaine in the classroom while she thought no one was watching.

On Tuesday morning a group of students were waiting to enter Samantha Cox's English class at Lake Central High School, Indiana, when they noticed her fussing over what looked to be a white substance on a book.

One of the students then took out their smartphone and began filming the 24-year-old teacher through the classroom door's window as she performed her actions.

Unaware of the student filming, the footage shows Ms Cox separating white lines on a book on her lap before appearing to bend down as if to snort it.

The unclear footage was enough to make school officials get in touch with police once the video was uploaded to YouTube.

"When I actually watched the footage again and again and I realised that my English teacher just did cocaine," the student who filmed the teacher told US news channel WGN9.

Police arrived at the school and arrested MS Cox on charges of possessing a controlled substance and drug paraphernalia.

The Northwest Indiana Times reports that the substance recovered by police was a mixture of cocaine and heroin.

Ms Cox was in her second year of teaching at the school and was described by students as "well liked".