Brooke Mathison was a mysterious female individual, who once used the names Angela Lindsay and Claudine Poyet as an alias. At some point in her life, she became a prominent member of the True Believers.
She blackmailed Jason Atwood into falsely confessing to the murder of terrorist leader Majid Nassar in exchange for his son Luke's safety. However, she did not hold her end of the deal, and Luke's body was found near a river.
However, this would later come back to bite her, as she was fatally shot by Jason.
Brooke was born in Seoul, South Korea to a soldier who would later be discharged from his duties. Afterwards, her life spiraled downhill. She began appearing in many areas of the United States and at some point affiliated herself with the True Believers, the perpetrators behind the Capitol Bombing.
Brooke took on the alias a contractor named "Claudine Poyet", and met Charles Langdon after he went through a divorce. He showed her great affections, but Claudine did not return them. Using her self-claimed status as a contractor, she began asking him for inside information about things like highway projects, but eventually she asked for the threat assessment on the Capitol renovation; Room 105. This information would presumably be given to Peter MacLeish.
Some time later, she met up with Peter MacLeish, who asked how many people had to pay before it was all over, to which she responded just one.
When Jason was looking for his son after he didn't return home, he came across Brooke. The latter took out a phone showing Luke eating an ice cream cone. Jason drew a gun and demanded the location of his son. In response, Brooke threatened that Luke will die along with his wife Yvette should anything happen to her, to which Jason reluctantly stood down. She then gave him a phone and told him to make an appointment with President Kirkman, while doing exactly as she instructed. This would later turn out to be a false confession to Majid Nassar's murder.
However, she did not hold up her end of the bargain, and killed Luke some time after, whose body was discovered by Jason near a river. She went to a law enforcement office to find out the whereabouts of Hannah Wells, using the name "Angela Lindsay" as an alias. After discovering she was released from custody, she contacted Beth MacLeish, who promptly drove to her husband Peter's location.
After Hannah discovered her true identity, she went to her address and was attacked by Brooke. She managed to get Hannah in a choke hold until Jason Atwood held her at gunpoint. Brooke attempted to goad Jason into shooting her, but to no avail. As a last resort, she tried to pull out a hidden sidearm only to be shot by Jason and Hannah. They then both discover that she had a thumb drive that contained simulations of U.S landmarks exploding, which turned out to be decoys.
- She was born on February 22, 1977.