The Company(Season 7, Episode 20) ION. Morgan's missing cousin, Cindi, reappears, and Morgan must come clean about a lie he told concerning her. In addition, the BAU reopens the investigation into Cindi's disappearance.
Selenium in biology. Although it is toxic in large doses, selenium is an essential micronutrient for animals. In plants, it sometimes occurs in amounts toxic as forage, e.g. locoweed. Selenium is a component of the amino acids selenocysteine and selenomethionine.
Selenium is found in metal sulfide ores, where it partially replaces the sulfur. Commercially, selenium is produced as a byproduct in the refining of these ores, most often during production. Minerals that are pure selenide or selenate compounds are known but rare.