The FBI today said it wants to install 150 digital billboards in 20 major U.S. cities in the next few weeks to show fugitive mug shots, missing people and high-priority security messages from the big bureau.

The initiative is made possible through a partnership with Clear Channel Outdoor, the advertising company that’s providing the space as a public service.

The billboards will let the FBI highlight those people it is looking for the most: violent criminals, kidnap victims, missing kids, bank robbers, even terrorists, the FBI said in a release. And the billboards will be able to be updated largely in real-time —right after a crime is committed, a child is taken, or an attack is launched.

The FBI said it tested its first billboard in the Philadelphia area in September, with crystal-clear images of 11 of its most violent fugitives on eight billboards and a 24-hour hotline for the public to call. The billboards paid quick public safety dividends. In October, two fugitives were captured as a direct result of the publicity, the FBI said.

Chicago, Las Vegas, Los Angeles and Miami will be among those cities provided with the new billboards, along with Milwaukee and Philadelphia.The FBI said Atlanta, Cleveland, Indianapolis, Memphis and Minneapolis will also get the billboards, as will Akron, Ohio; Columbus, Ohio; Albuquerque, N.M.; El Paso, Texas; Des Moines, Iowa; Newark, N.J.; Wichita, Kan.; and the Florida cities of Tampa and Orlando.

Using digital billboards to put pressure on criminals is not an entirely new concept. According to a CNN report, in September, Florida authorities arrested a drug suspect two weeks after his photo was displayed on a billboard in Daytona Beach. A tipster who saw the suspect's picture found him sitting in a McDonald's. The billboards have also been useful in disasters. When an interstate bridge collapsed in August in Minneapolis, billboards displayed an emergency message within 15 minutes, the report stated.

The downside is that only a small fraction of U.S. billboards are digital – 500 or so out of estimated 450,000 total signs, according to published reports.