CBS

Season 9: Episode 18 - Mascara

Mascara: Langston and the team must investigate the murder of his former student after CSIs are called to the scene of her murder.  The young woman was researching the 11 year old case of three women killed by a known, but since dormant, serial killer for her graduate thesis; it appears she got close to figuring out the killer's identity and the killer came out of hiding to make sure she did not expose him.