Brianna is Cross' wife and was also a detective before being promoted. She first appeared in Double Cross, having started a relationship with Alex and falling in love with him. Bree is described as a tough Bureau detective and is put on the DCAK case, which she works with Alex and Sampson. At the beginning and near the end of the novel, she professes her love for Alex. In Cross Country, Bree and Alex's relationship continues to grow stronger. She helps him investigate The Tiger, especially when his family is kidnapped by the killer also. In I, Alex Cross, Bree is shown living with Alex at the Cross home. She continues to stay at the Cross house to take care of Nana Mama, after Nana nearly dies. In the end of the book, Alex proposes to her and she happily accepts. In Cross Fire, Bree and Alex look forward to their wedding, while at the same time dealing with Kyle Craig. They get married after facing off against Kyle Craig "the Mastermind" one final time. At the end of the novel, Kyle is killed and Bree and Alex are finally enjoying a life of peace together. In Kill Alex Cross Bree discovers a homeless girl trying to steal from the Cross house, and later agrees to adopt her due to Nana's wishes. In Merry Christmas, Alex Cross she seems distraught and annoyed that Alex must be away from his family on Christmas. However, at the end of the novel, Alex and her share a dance while on a double date with Sampson and Billie, and they share a kiss. In Alex Cross, Run she is distraught and wants vengeance when Ava, a young girl she and Nana adopted, is burned alive. She and Sampson assist Alex in capturing Ava's murderer and killing him. At the end of the novel, she and Alex continue to recover from the death of Ava and their love for each other remains strong.