Updated

The tipster's account was grim. A woman had suffered broken ribs and a punctured lung at the hands of a man who for nine years had been forcing her into prostitution.

That confidential call was received in late January by the National Human Trafficking Hotline, which relayed the tip to an anti-trafficking task force operating in Virginia's Hampton Roads area. Within days, investigators located and interviewed the woman, and arrested the man, Naeem Lateef Odums. He was indicted on sex trafficking charges in March, pleaded guilty in June and will be sentenced in November to at least 15 years in prison.

"The hotline is extremely effective," said Michael Lamonea, a U.S. Immigration and Customs Enforcement special agent who assists the task force. "It's crucial to get folks the knowledge that there is help out there — there is a light at the end of the tunnel."

Many Americans know little about the hotline beyond the billboards and other public service ads providing its phone number. Yet people in the anti-trafficking field say it performs well at two vital roles — as a conduit for people to report suspected trafficking and as an immediate resource for trafficking victims in need of help.

As of December, the hotline will have been operating in its current form for 10 years. In 2008, it received 3,514 calls, including just a few hundred from trafficking victims. In 2016, there were 26,727 calls, including more than 4,600 from victims, fielded by 55 specially trained staffers at the hotline's call center.

The toll-free hotline is available to field calls 24 hours a day, every day of the year. Callers can speak with the staffers in English or Spanish, or in more than 200 additional languages using an interpreting service.

A Tennessee woman, Samantha Floyd, called the hotline in 2013 while taking refuge in a St. Louis church after fleeing from men who were sexually exploiting her in Nashville. Floyd said the woman who answered the call spoke with her for nearly an hour, eventually referring to her to a local advocate for trafficking victims.

"The advocate was just amazing," Floyd said. "She let me text her day or night. She connected me with a trauma therapist. Honestly, she kept me sane and probably kept me alive."

An early version of the hotline was created by the Department of Health and Human Services in 2004, but it took its current shape in 2007 when HHS chose Polaris, a Washington-based anti-trafficking nonprofit, to operate it. Its budget is now $2.85 million, including $1.5 million in federal funding and the rest from donors.

"We've been working hard at reaching more survivors and building trust so the number of calls would increase," said Polaris' executive director, Bradley Myles. "We wanted to offer a lifeline to those who were stuck in a trafficking situation and didn't know how to get help."

The largest number of calls comes from Houston, New York and Los Angeles; the most calls per capita are from Washington, D.C., Atlanta, Las Vegas and the Florida cities of Orlando and Miami.

Myles attributed the rise in calls to increased awareness of the hotline and its confidentiality policy. All communications are kept confidential unless a caller consents to being connected to law enforcement or a social service provider, or if the caller reports a situation of imminent danger.

Many states have laws requiring or encouraging the posting of signs with information about the hotline. Locations covered by such laws include hotels and motels, truck stops, bars and night clubs.

Myles wants to expand ways that people can reach the hotline — for example, through social media apps. He expects more people will seek to text the hotline, rather than call, and hopes to raise funds so texting will be possible 24 hours a day, instead of the current 8-hour window.

Polaris uses hotline data to identify trafficking trends and develop profiles of traffickers. A report issued this year identified 25 distinct types of human trafficking in the U.S., affecting sectors ranging from traveling carnivals to the forestry industry.

One of the hotline's strong points is the potential for rapid response.

Rebecca Bender, an Oregon-based advocate for trafficking victims, said she recently received a late-night call from a frightened woman in Baton Rouge, Louisiana, who was trying to escape from her trafficker.

Bender called the hotline and was swiftly given contact information for four victim-support organizations in Baton Rouge. Three were closed for the night; the fourth was open and immediately dispatched a vehicle to pick up the woman at a McDonald's where she was taking refuge.

In another recent case, Bender received a call on behalf of a woman entangled in sex trafficking in Florida who'd been sexually assaulted and was desperate to get away from her trafficker. Bender called the hotline, which arranged for the woman to fly to Utah within 24 hours using a voucher obtained through an arrangement with Southwest Airlines.

About 80 percent of the calls relate to sex trafficking; the rest concern labor trafficking.

One such case was uncovered through a hotline tip relayed to Teresa Collier, an intelligence analyst with the Alabama Law Enforcement Agency. She said police, acting on the tip, determined that a woman had been forcing her 10-year-old daughter to work at jobs such as house cleaning, abusing her and pocketing her earnings.