Vanessa is a waitress at a country bar and also secretly a serial killer who spent the last eight years devoted to getting revenge against the Marines responsible for abandoning her and her friends in an abandoned shipping container that had been brought to the U.S from the Philippines.
Not much is known about her early life but it's revealed that she was the youngest of the group of girls and the others gave her their food in the hope that she would survive but eventually at the cost of their own lives as they all starved to death, leaving Vanessa as the sole survivor of the group and being forced to spend many nights sleeping with their lifeless corpses.
Eventually, Joe Sacco saved Vanessa from the container but it wasn't long before Vanessa's murderous urges and her need for vengeance took hold of her.
Having been driven to the edge and consumed with grief and rage over the deaths of her friends, Vanessa enacted her revenge, targeting all the Marines in Sacco's group including Sacco himself whom she killed in the sewer.
The first four victims she murdered only completely disappeared without a trace and because of this, they were all regarded as deserters by the Marine Corps after thirty days and it wasn't until NCIS found a link between them that it was realized that the killings were connected.
She also attempted to kill Special Agent Anthony DiNozzo who was protecting Bill Atlas but luckily, his colleagues Leroy Jethro Gibbs and Caitlin Todd who had been tracking Sacco from the moment they had entered the sewer intervened at the last second, saving Atlas from death while also taking Vanessa into custody after Tony disarmed her.
Vanessa would target her victims by drugging their drinks whenever they were in a bar where she worked. Once outside, the victim would lose consciousness due to the drug taking effect.
While the targets were out cold, Vanessa would take them to a empty, filthy sewer and remove anything that the victim could use to help them escape.
She would then keep the victims imprisoned in the same room for days or months on end, essentially recreating the horrors that she herself had suffered.
She would even release bees into the cell where they would sting the victims and leave them in great pain and also during that time, she gave them a silver cross which served as a reminder to what had happened to her and her friends.
Eventually, and as a result of not getting any food, the victims who had been driven insane eventually starved to death.