Who is Betsey Cavalierre from Violets Are Blue and what is their importance?

Betsey Cavalierre was Cross' partner before her death. When the novel begins, we learn that she was also his lover. The Mastermind killed her to send a message to Cross. After Cross learns the Mastermind is really Kyle Craig, Craig admits that he killed Betsey as she began to suspect that he was the Mastermind. Because of Betsey's cruel fate, Cross approaches other female law enforcement officers with caution. Betsey never physically appears in the nove because she is dead before it begins.