Lorrain Thorson is the mother of murder victim, Lieutenant Clea Thorson. After Abigail Sciuto became fixated on solving the puzzle that Clea had created, Abby's boss, NCIS Special Agent Leroy Jethro Gibbs sought Lorrain's help in breaking Abby's fixation. Having realized that her daughter and Abby had a lot in common with one another due to their respective scientific backgrounds, Lorrain told Abby to put emotion aside and was successful in making sure that Abby regained her true priorities.