Samantha 'Sam' Spade is a Special Agent in the New York City FBI missing persons case squad led by Special Agent Jack Malone.
She has a son, Finn.
She was raised in a poor, troubled home in the town of Kenosha, Wisconsin and as a result is particularly empathetic to kids in troubled situations.
She was very unhappy as a teenager and tried to run away when she was sixteen, but was stopped by her mother and a policeman.
For a short time while she was eighteen, Sam was married, but the marriage didn't last long. She also had an ex-boyfriend named Eric Keller, who is a police officer. In the 21st episode of the first season it also became clear that she has had sexual relations with her superior Jack Malone at least one time.
In 518, Sam's estranged older sister Emily visited. When Samantha was fourteen, she killed her mother Patricia's then-boyfriend with a shovel because she caught him sexually abusing Emily (519). They buried him in the woods next to the cabin and eventually grew distant from each other. Samantha learns that as a result of this abuse, Emily had a son, Randy, who now has cancer so she sought a bone marrow donor. Sam is not a match but her mother is a possibility.
Spade received her name because her mother was a fan of fictional detective Sam Spade and The Maltese Falcon, both created by Dashiell Hammett.