The app and technology could save detectives days and weeks of sorting photos and speed their response to a location of a pimp or a victim, said Molly Hackett, one of the three local women who came up with the idea of collecting hotel photos.

How effective is it? One of its inventors, Abby Stylianou, a Metro High School graduate with a passion for computer imaging analysis and social justice, said test trials are highly encouraging. About 85 percent of the time, the computer algorithm is able to deliver a hotel match in the first 20 photos it returns from the search.

If successful, the app has the potential to put a dent in the illicit sex trade that markets photos of minors on the internet through advertising sites such as Backpage.cοm. That site generates more than $37 million a year in revenue.

The FBI is also excited about the new technology.

“In this case, individual citizens who want to help stop sex trafficking but didn’t know how, now have a tangible way to contribute,” said William Woods, special agent in charge of the FBI’s St. Louis Division.

One social justice group, the Congregation of the Sisters of St. Joseph, is so hopeful about the app’s potential, it donated a $100,000 matching grant toward technology development.