operation spanned august 2014 to march 2015 in houston .
one male narcotics officer posed as a senior in two high schools .
six students were arrested , three aged 18 , one 17 and two minors .
they have received a total 10 drug-related charges .
cocaine , marijuana , xanax and tramadol were seized in the bust .
police have not released any information about the undercover officer .