Sgt. Det. Tommy Saunders
Boston Police sergeant detective who was working crowd control at the finish line and became embroiled in the manhunt.
- Berserk Button: When DesLauriers won't allow victim Martin Richard's corpse be moved until the crime scene is processed, because his wife can't conceive.
- Composite Character/Expy: Of the massive number of different police officers involved at each stage of the manhunt such as Sgt. Det. Danny Keeler.
- Handicapped Badass: He's got a pronounced limp compliments of kicking in a door the night before the race, which he often needs to support with a knee brace.
- Reassigned to Antarctica: His assignment to Marathon finish line crowd control is the final bout of punishment received over a previous altercation with another officer.
Carol Saunders
Tommy's wife.
- All There in the Manual: The initial synopsis said she was a nurse, but she's never shown anywhere near a hospital.
- Dark and Troubled Past: Tommy tells Evans that she's barren.
Commissioner Ed Davis
Commissioner of the Boston Police Department.
- Da Chief: Depending on how you view the Boston Police command structure.
- Historical Domain Character
Supt. William Evans
Superintendent of the Boston Police Department.
- Adaptational Attractiveness: Here's the real guy◊ and here's the guy playing him.◊
- Da Chief: Depending on how you view the Boston Police command structure.
- Historical Domain Character
- Rank Up: Promoted to commissioner after Davis retired.
Mayor Tom Menino
The Mayor of Boston.
- Demoted to Extra: Finally appears in the incident command center on April 19, mainly to voice concerns about Deval's shelter-in-place lockdown order.
- Historical Domain Character
Special Agent in Charge Richard DesLauriers
The head of the FBI's Boston field office.
- Berserk Button/Beware the Nice Ones: He is calm, polite, and considers the ramifications of every command decision he makes...until Fox News threatens to release the Tsarnaevs' photos on April 18, at which point he loses his temper about finding whomever leaked the photos to them.
- Da Chief: Of the local FBI field office.
- Historical Domain Character
- Pronouncing My Name for You: both Tommy and the black-ops interrogation team have to be told his last name is pronounced "da-lore-ee-ay."
Sgt. Jeffrey Pugliese
Patrol sergeant of the Watertown, Massachusetts Police who engaged the Tsarnaevs on April 19.
- Deadpan Snarker: "I gotta fucking quit smoking" after apprehending Tamerlan.
- Firing One-Handed: After reloading during the shootout, he fires practically from the hip at Tamerlan.
- Hidden Depths: A making-of featurette showed him making marinara, complete with his own "Jeff's Spice" spice mix.
- Historical Domain Character
- Nerves of Steel: The man's response to gunfire and explosions? Calm sarcasm, tactical planning, and accurate shots that take down Tamerlan.
Dun Meng
The civilian who was carjacked by the Tsarnaevs and was later able to relay their location to the police.
- Action Survivor: He manages to escape being held hostage by the Tsarnaevs and screws them over big-time.
- Historical Domain Character
- Humble Hero: Despite all of the complements and accolades he's received for his actions, he insists that he is a victim rather than a hero and freely admits he was just trying to save his own life when he jumped out of the car.
- Reality Is Unrealistic: Meng really did memorize his car's GPS tracking code.
- Spanner in the Works: When Meng makes his successful break from the Tsarnaev brothers, he effectively dooms them by providing the police valuable information to find them, such as his vehicle's GPS number.
Li
- Brainy Brunette/Wrench Wench: She's an engineering major at MIT working on a robot dog.
- Canon Foreigner: real-world version.
Jessica Kensky
Patrick's wife, a Marathon spectator who was injured in the attack.
- Historical Domain Character
- Hospital Hottie: Averted; she's an attractive oncology nurse at Massachusetts General Hospital but wears scrubs. The closest she gets to sexiness is in her rather unremarkable sleepwear while in bed on April 15.
- Nerves of Steel: Still dazed by the overpressure wave of the bomb explosion, with her own legs so shredded by shrapnel that they eventually have to be amputated and her jacket on fire, she still has enough presence of mind to use her pocketbook strap as a tourniquet for Patrick's own injured leg.
Patrick Downes
Jessica's husband, a Marathon spectator who was injured in the attack.
- Fake Nationality: Patrick is American; Christopher is British.
- Historical Domain Character
Tamerlan Tsarnaev
One of the bombers.
- Big Bad: He is responsible for the terrorism plot.
- Big Brother Bully: He outright threatens his younger brother not to keep screwing up, otherwise he’ll shoot him dead.
- Conspiracy Theorist: Is a zigzagged 9/11 truther.
- Historical Beauty Upgrade: Tamerlan Tsarnaev, played by Themo Melikidze.
- Historical Domain Character
- Hypocrite: Along with his brother, rants of his conspiracy to Meng about his hatred to the US government because he believed they orchestrated 9/11 to generate hatred for Muslims, yet it doesn't occur to him that what they've done will do exactly that. Not only that, but have already planned to do another bombing attack in New York, all in the name of their extremist beliefs. He never lives to see it happen.
- Insane Troll Logic: Rants about how the US's actions forced him to do what he did. No one buys it.
- Karmic Death: Not only is he shot by the Watertown Police, he's run over by his own brother, and as Stephen Colbert pointed out, died at Beth Israel Deaconess Hospital.
- Miles Gloriosus: He considers himself to be a strong, wise crusader doing great work on behalf of his faith. Once the authorities learn about him and his background, Ed Davis dismisses him as a coward lashing out because his dreams of being a boxer didn't pan out. He later gets himself killed because of his poor decision making.
- Never My Fault: He believes Manny got away because Dzhokhar distracted Tamerlan. Nevermind that Dzhokhar wasn't even in the car (he was only getting food to stock up for their long road trip to their next attacks), and that Tamerlan was busy on his phone, it was somehow all somehow Dzhokhar's fault. This comes back to bite Tamerlan as it causes Dzhokhar to have a private Rage Breaking Point and then give his brother his well-deserved Laser-Guided Karma while fleeing from the cops.
- Sex Is Evil: Brings up fornication in his rants.
Dzhokhar Tsarnaev
One of the bombers.
- Arson, Murder, and Jaywalking/Sex Is Evil, and I Am Horny: Blithely says to Tamerlan "I'm a fornicator" during one of Tamerlan's rants justifying their actions, and one FBI Evidence Response analyst notes that he had more Internet pornography in his possession than Osama bin Laden.
- The Dog Bites Back: He’s constantly pushed around by Tamerlan, blamed for Meng getting away, at one point threaten to be killed while Tamerlan is in the middle of a Villainous Breakdown. He gets payback during the Watertown shootout by abandoning Tamerlan, but not before running him over after he’s fatally shot by the cops.
- The Dragon: He is mostly subordinate to his older brother Tamerlan.
- Dragon Their Feet: He ultimately outlives his brother.
- Historical Domain Character
- Rage Breaking Point: Right before the Watertown shootout, Dzhokhar is seen angrily muttering over how Tamerlan keeps blaming him for everything that goes wrong, complete with multiple Precision F-Strike of the "F" word. He finally gives his brother his Laser-Guided Karma by running him over when trying to escape, which proves lethal to Tamerlan, who is left lying in the street, completely in shock, as Pugliese and the other sergeant restrain him, though there wasn't much reason for it with his condition and unable to fight back anymore.
- The Stoner: It's said he was the biggest marijuana dealer at UMass-Dartmouth.
- Would Hurt a Child: During the marathon, he walks by several children and sees a stroller, but he doesn’t hesitate to leave the bomb just a few feet away. The youngest of the fatalities is a 8 year old boy (the toddler in the stroller traumatically screams from a bloody head wound caused by the bombing, but survives). He and his brother have no regrets.
Katherine Russell
Tamerlan's wife.
- Historical Domain Character
- Lady Macbeth: She doesn't necessarily encourage her husband in his endeavors, but she clearly supports him and seems quite proud of him during her interrogation.
- Parental Neglect: During the police interrogation, she refuses to give up information, even when she’s at large risk of losing custody of her young daughter. Even the cops felt bad for the kid.