Tracey is mentioned in both The Cuckoo’s Calling and Career of Evil. She was Strike’s fellow SIB officer and girlfriend. Lucy had high hopes that her brother would marry Tracey, but the couple broke up, perhaps in part over the disagreement of whether or not to have children. Strike has always been opposed to becoming a father, and Tracey ended up marrying one of their mutual friends and having a daughter. Strike intended to send them flowers, but forgot.