While initially depicted as a protagonist, Maria LaGuerta, who serves as the superior officer to main characters Dexter and Debra Morgan, evolves into one of the primary antagonists by Season 7.

According to the dialogue, her family is located entirely in Cuba, and she mentions the experience of being alone in a foreign land, suggesting that she was sent to live in America independently.

In the series' beginning, LaGuerta is depicted as a determined and ambitious woman with a stronger aptitude for political maneuvering than practical police duties.

In the conclusion of the first season, Captain Tom Matthews, her superior, removes her from her leadership position due to her inability to apprehend the Ice Truck Killer.

When her friend, former partner, and former lover, James Doakes, becomes the primary suspect in the Bay Harbor Butcher case, LaGuerta endeavors to vindicate him.

She receives information from a dubious source regarding two Special Forces missions undertaken by Doakes, which coincide with the deaths of two Butcher victims.

In the season finale, Doakes and drug dealer Jose Garza are discovered dead in an apparent accidental explosion, leading to the case's closure.

Following Doakes' demise, LaGuerta appeals to police officers for contributions to his memorial fund, refusing to accept the notion that her deceased friend was a serial killer.

However, Dexter manages to persuade her that pursuing the case would only inflict further pain upon Miguel's family and the community, and even if successful, the evidence would be insufficient.

Recognizing the significance of their jobs for their identities, Batista and LaGuerta decide to end their relationship and provide signed affidavits to confirm this.

As LaGuerta and Matthews delve into the case, they revisit the cabin where Doakes died and uncover evidence linking Santos Jimenez to the deaths of Dexter and Brian Moser's mother.

Despite this setback, LaGuerta remains determined to apprehend Dexter, especially after finding circumstantial evidence linking him and Debra to the scene of Marshall's death.

In Darkly Dreaming Dexter, LaGuerta is depicted as a person who engages in political gamesmanship and exhibits manipulative behavior.