In this Oct. 24, 2013 photo from the Worcester County Sheriff’s Office shows service dog Nikita visiting a criminal justice class at Sutton Memorial High School in Sutton, Mass. Nikita, the mutt from a Massachusetts animal shelter who got a new life as a K-9 drug-detection dog, stars in an upcoming episode of a new PBS series called “Shelter Me: Partners for Life.” The Worcester County sheriff’s department in central Massachusetts turned to the shelter for help when there wasn’t enough money in the budget to replace its retiring tracking dogs.