Before Season 2Edit
Marcy met Bob Lindhoff, who was 17 years older than her, and they got married. Still, Bob usually got obsessed with other women and Marcy allowed him to bring them to their bed. When Marcy noticed Bob was looking at their neighbor, Kayla, she got a little jealous. Bob asked Marcy to talk to her to see if she would agreed to join them, but Kayla wasn't interested. Still, she lured her into their apartment and they kidnapped her. After doing so, she recommended him to sever her arm and throw it in a dumpster.
When Detective Dutch Wagenbach started working the case of the disappearance of Kayla LeSeur, he visited Marcy and Bob Lindhoff, who were Kayla's neighbors. When he questioned them, Marcy claimed having seen someone outside Kayla's apartment. Dutch asked them to stop by the Barn to see if they could identify the person. At the Barn, they managed to describe him and have a sketch of the suspect made. After they were finished, they left.
After they returned, they started packing with the intention to leave. They also put Kayla on the trunk of their car. As they were driving out, Dutch saw them and asked them if they could get back to the Barn to identify the suspect. Dutch suspected that Bob was a sadomasochistic and controlling husband, so he interrogated Marcy trying to make her confess his culpability. During the interrogation, Marcy started crying and denied any involvement of her or Bob in Kayla's disappearance.
When a call was received about a homeless guy threatening people with a "machete", Dutch thought it was the Kayla's kidnapper, so he had Bob and Marcy released. Bob and Marcy tried to flee the state, but were eventually intercepted by the police after they found evidence against them in their apartment. After Dutch and Claudette found Kayla's dead body in the trunk, Bob admitted everything had been Marcy's idea. Dutch asked her why in disbelief as she mocked him while being arrested.
After she was arrested, Marcy made a deal with the District Attorney where she would get only 8 years in exchange for her testimony against Bob. The D.A. agreed to avoid any more publicity on their botched investigation. They arranged for Dutch to take her statement and brought her to the Barn again.
Marcy was taken into one of the interrogation rooms, where Dutch met with her. He congratulated her on her plea bargain but told her that she deserved as much punishment as Bob. He then corroborated with her the facts of the case. When they were finished, Dutch asked her why she thought she could fool him. Marcy simply told him that she let him fool himself.