GEOFF BENNETT: More than 100 million viewers are expected to tune into the Super Bowl on Sunday being held in the Phoenix metro area.

The stadium is expected to be packed with more than 70,000 people on hand to watch the Kansas City Chiefs and Philadelphia Eagles square off.

But big sporting events also can have a darker side that isn't talked about much publicly, a notable rise in local sex trafficking.

Stephanie Sy spoke about this with Dominique Roe-Sepowitz, an associate professor at Arizona State University and the director of the university's Office on Sex Trafficking Intervention Research.

STEPHANIE SY: Dominique Roe-Sepowitz, thank you so much for joining the "NewsHour."

We have all seen the ads in the airport bathrooms, heard the public announcements warning about sex trafficking with sex trafficking help lines.

It seems like there's a lot of public awareness these days around this issue.

Is it true that sex trafficking actually does increase during the Super Bowl?

DOMINIQUE ROE-SEPOWITZ, Arizona State University: What we found in Arizona and in New York and in California when the Super Bowl has traveled is, indeed, there is a lot of sex trafficking.

So, in our research, we have found that the buyers that are looking for people to purchase for sex, whether they're children, adults, trafficked, not, are mostly local people.

So the people that celebrate these big events and a bigger, broader market of victims being brought to town are actually local people.

STEPHANIE SY: And there are more of them around an event like the Super Bowl?

DOMINIQUE ROE-SEPOWITZ: It's hard to measure.

This is an illicit business, like drug dealing, drug trafficking.

Sex trafficking is hard to measure.

The things that we can measure it by are how many ads are online, how many people call to buy sex, how many people we see, how many cars are driving up and down the streets where prostitution is sold.

And all of those are really weak metrics for a very serious problem.

STEPHANIE SY: What are we really talking about when we talk about sex trafficking?

Are we talking about paid sex with minors, or are we talking about also a greater demand for willing adult sex workers?

DOMINIQUE ROE-SEPOWITZ: The people who are being sold are often coerced and forced.

Many are under the age of 18, so they cannot consent to sell sex.

And those who are over 18 initially may have said it was OK.

They fell in love with the person who's coercing them.

They got talked into it so they could make some money for drugs.

But, almost always, we find that people withdraw their consent, and that withdrawal is met with violence.

So, one of the important pieces is, who does the trafficker target?

Who are -- is being bought and sold?

And the vulnerabilities that we see is very similar across the board.

They're mostly women, from the research we have.

They're mostly people whose families are disconnected.

And so I can say to moms out there, watch your kids, be smart, look online, see what people are doing.

But the chances of someone grabbing their child to prostitute them in our community during the Super Bowl is very, very low.

STEPHANIE SY: Dominique, one of the criticisms I have heard is that it's a myth, that there is not increased sex trafficking during the Super Bowl, and, in fact, what could end up happening is police officers criminalizing sex workers who might be in a position to choose that line of work and not be exploited.

DOMINIQUE ROE-SEPOWITZ: It's a really difficult paradox that we have.

Prostitution, selling sex is illegal in Arizona.

I think it's a balancing act.

Especially as a social worker, I believe that people should be able to do whatever they want with their body.

But what we do know from the research in Phoenix, those who are arrested for prostitution, at some point during their engagement with the criminal justice system, identify as being a victim of sex trafficking.

So if one out of 10 says, I'm independent, I'm on my own, and nine out of 10 say, I'm in trouble.

I need help, somebody, give me a pathway out, it's a difficult decision, I think, for people to decide.

And I can say that, in the Arizona community, we are really paying attention to the nine, the nine out of 10 who say, I'm a victim of trafficking, and I need someone to give me a pathway out.

STEPHANIE SY: Given all the mobilizations that you're talking about ahead of this weekend's Super Bowl, what do you expect will happen?

DOMINIQUE ROE-SEPOWITZ: I think that there will be a number of traffickers.

I think the traffickers should pay attention and know that law enforcement is paying attention, that the community is activated, that we're looking and helping.

And I really think we're going to see a pretty massive set of events that are arrest-based.

What I would love to happen is for us to talk about this at our kitchen tables, at our -- at our -- while we're watching TV, on school buses, in our cars as we drive kids to school, really think about, what does trafficking mean to our community?

And how do we have an environment that allows it to happen here?

What can we do to change that from ever happening again?

STEPHANIE SY: Dominique Roe-Sepowitz with Arizona State University, thank you so much for joining us.

DOMINIQUE ROE-SEPOWITZ: Thank you so much for having me.