Federal and local Denver metro area law enforcement agencies busted 22 alleged prostitutes last week, all of whom advertised on two separate Internet sites, according to the Federal Bureau of Investigation.

The two-day crackdown on Wednesday and Thursday reeled in escorts who advertised on www.preferred411.com and www.denverbackpage.com, according to an FBI news release.

Investigators found that www.preferred411.com was "used nationwide to advertise for the purposes of prostitution and to verify 'clients,'" according to the release.

Twelve of the arrested women advertised on that site.

"Previous investigations nationally have shown links to this type of website may involve human trafficking violations," the release said.

"We will continue to investigate crimes involving prostitution in the Denver Metro area and keep up with the evolving technology used by people in this industry," said Denver Police Lt. James Henning

Agencies that participated in the arrests included Denver, Aurora and Lakewood police departments, FBI Denver Division, Colorado Trafficking and Organized Crime Coalition and the Innocence Lost Task Force.

Tom McGhee: 303-954-1671, tmcghee@denverpost.com or twitter.com/dpmcghee