Lara Hill was a Lieutenant who worked in the Pentagon's cryptography department.
She was due to go to NCIS for an interview regarding the possibility of a mole being in the department but ended up being murdered by her C.O. Kevin Dorn.
Dorn, who was the mole, placed Hill in a choke-hold, rendering her unconscious after ten seconds before pulling the trigger with Hill dying instantly.
To cover his tracks and attempt to take heat away from him so that he could preserve his cover, Dorn disguised the murder as a suicide and also attempted to frame a foreign spy, Simon Roca as a diversion but thanks to Abigail Sciuto, Dorn's role in Hill's murder was eventually discovered and he was arrested.