Who is more likely to kill you? Someone you know or someone you don't?
If you believe what you see on television, it's a stranger, and that concerns researchers at the Mayo Clinic, who say the way the shows "CSI" and "CSI: Miami" depict homicide could create a public health risk.
Every year, 43 million people tune in to those popular TV programs, which follow a forensics team as it investigates complicated, sometimes bizarre murders.
Chris Janish, a Mayo medical student, analyzed the shows, and cited one particular episode as a perfect example.
"You have a serial killer team, both Caucasian males, who prey on young women running through a college campus at night," Janisch explained.
Television investigators use clues to crack the case. In this episode, all of the victims' hands are painted blue. By the end of the show, the suspect tells investigators how he killed the women.
But medical student and researcher Melanie Buskirk says that's not how murder usually happens. She says researchers compared homicide statistics from the Centers for Disease Control to the popular TV shows. According to the CDC, 75 percent of murder victims are killed by someone they know.
"Their spouse, an acquaintance, a friend or a co-worker," she said, "versus on the "CSI" shows, [where] it was largely strangers who committed the crimes."
Who gets killed in these shows doesn't reflect reality either.
Eighty percent of the victims on "CSI" and "CSI: Miami" are white. But the CDC says Caucasians make up 35 percent of victims, while African Americans make up 50 percent.
Buskirk says the numbers are even more egregious when it comes to alcohol use.
Nationally, 60 percent of the people who committed a violent crime had used alcohol.
"Four percent of the offenders [on 'CSI'] had used. And if you look at the offender data, 60 percent in real life versus 4 percent on TV," said Buskirk. "That ... highlights what we're seeing on TV, and how it doesn't quite correlate with what we're seeing with the national statistics."
Psychiatrist Dr. Tim Lineberry, who led the study, says it is likely the "CSI" shows feed into a fear of strangers, or a belief that domestic violence isn't a widespread problem.
According to Lineberry, research shows people learn about public health from television.
Just a few years ago, another study by the Kaiser Family Foundation asked viewers what they learned about medicine from the popular television program "ER."
"Fifty-three percent of regular viewers have said they have learned about important health issues from ER," Lineberry said. "Fifty-one percent have talked to friends or family about health issues raised in the show."
To show just how effective TV shows can be in changing public health policy, Lineberry points to an episode of "ER."
In it, the dramatic turn in the story starts with the surgical safety checklist. When the check finds there is none of a special solution on hand, a nurse has some sent in, saving the life of the patient.
Lineberry says a few months after the show aired, the New England Journal of Medicine published an article on the surgical safety checklist.
Lineberry says that can't happen in every episode, but he thinks CSI could, on occasion, base more of its storylines on reality, and not lose a bit of the drama.