Bad Blood
Bad blood.jpg
Season 15
Number 3
Writer Tom Mularz
Director Louis Milito
Original Airdate October 12, 2014
Previous Episode: Buzz Kill
Next Episode: The Book of Shadows

Bad Blood is the third episode in season fifteen of CSI: Crime Scene Investigation.


Sara and Greg are quarantined after responding to a crime scene that’s contaminated with a deadly pathogen.


There’s blood all over the living room, spattered on the dingy curtains and pooled on the floor. The body of a scruffy man is lying in the largest pool of blood, but the team doesn’t know who he is. He pays cash for the rent, and he uses a fake name. There’s a single bullet wound in the man’s neck, with a corresponding shell casing on the floor. He bled out, but that doesn’t explain the blood spatter and smaller pools around the room; this evidence suggests a struggle, and the team hopes the killer might have left some blood behind too.

As Sara leans down to get photos of the victim’s body, she spots something frightening: the eye closest to the floor is open and bright red, and there are lines of dried blood trailing from his eye, nose and mouth. The man was sick. She alerts Greg, who immediately realizes the danger they’re in. Sara calls the CDC while Greg looks around at the blood coating the room. The pathogen could be in the blood—or worse, in the air they’re currently breathing. When the call goes through, Sara tells the person on the other end that they are dealing with a possible hemorrhagic fever. There’s one known victim—and two CSIs who are potentially exposed.

The house becomes a hive of activity as the CDC arrives to contain the crime scene and transport Sara and Greg to hospital quarantine. Protocol includes using UV light and formaldehyde fog to kill every living organism in the house. This should prevent further infection, but it will also destroy the blood evidence they need to catch their killer. Sara and Greg were able to upload their crime scene photos to the cloud before they were forced to abandon their gear, but that may be all they can save. The team needs to work together to identify the victim, diagnose his illness, and locate his killer before the disease can spread and claim more victims.


Main Cast

Guest Cast


Sara Sidle: Russell, I need you to do something for me.
D.B. Russell: Yes of course, anything.
Sara Sidle: If we are gonna die, we need to go done fighting, okay? So put us to work.
D.B. Russell: Neither one of you have my permission to die! You've got that?

See Also

CSI:Las Vegas Season 15
The CSI EffectBuzz KillBad BloodThe Book of ShadowsGirls Gone WilderThe Twin ParadoxRoad to RecoveryRubbery HomicideLet's Make A DealDead RailsAngle of AttackDead WoodsThe Greater GoodMerchants of MenaceHero to ZeroThe Last RideUnder My SkinThe End GameImmortality