A federal judge in El Paso on Thursday sentenced 35-year-old Marco Antonio Alferez.
The former dance instructor, who taught in five El Paso schools, pleaded guilty in August to sexual exploitation of children and to distribution of child pornography.
Alferez received a 30-year sentence for sexual exploitation and 20 years for child porn distribution. The sentences must be served consecutively.
Investigators in 2010 raided the educator's home and seized his computer.
Prosecutors say recordings made by Alferez contained about 400 child victims. Alferez, in some videos, can be heard off-camera asking children to undress and try on new items that he provided.
