Kate Keisel speaks to a large gathering to raise awareness of human trafficking outside the New Jersey Statehouse. (Mel Evans/AP)

For years, law enforcement has depended on tips from a D.C.-based national hotline to identify human traffickers in the U.S., where the State Department estimates some 15,000 people are trafficked to every year.

Now, that hotline is going global.

Using a $3 million award from Google, anti-trafficking groups Polaris Project, Liberty Asia and La Strada International plan to build an alliance of hotlines around the world. The D.C.-based Polaris Project, which is leading the effort, says it has already mapped out 70 anti-trafficking hotlines with whom they hope to partner.

Polaris currently runs the National Human Trafficking Resource Center hotline in D.C., which is funded in part by the Department of Health and Human Services, and has fielded more than 72,000 calls since it expanded in 2007. More than 3,000 tips have been shared with law enforcement from those calls, according to the group, and more than 8,300 victims of human trafficking have been helped with services or support.

Bradley Myles, CEO of Polaris Project, says he plans to apply learnings from the national hotline to the global one.

"What we've learned is the hotline has to be a general information line, tip line, training resource, and crisis line [all in one]," says Myles. "Law enforcement depends on the tips and leads we get from around the country... But I do think it's also important that we stay independent, that the hotline is run by civil society, so it's not seen as too closely aligned with law enforcement, and to build trust with callers."

Google is funding the effort on the heels of a summit it hosted on illicit networks in July, where the Internet giant found most illegal groups were involved in human trafficking in some way. Jared Cohen, director of Google Ideas, says despite hotlines that exist around the world to fight human trafficking, there isn't great coordination between them.

"If you call one hotline in one company, it generates data locally, but there is no way to correlate data with a hotline in another country," says Cohen. "[So we thought]: can you integrate all these hotlines so it doesn't matter which one you call? You need an integrated ecosystem to make the right response."