LAKELAND, Fla. -

Polk County detectives have arrested a total of 78 people during a four-day undercover prostitution investigation.

The Lakeland Ledger reports the investigation ran from Thursday to Sunday. It targeted online e-commerce sites where men and women advertise to commit prostitution and solicit for prostitution.

Of the 78 arrested, 18 admitted to being married and 31 had criminal arrest histories. Nine were registered felons and have a combined total of 339 past charges, including armed robbery, aggravated assault with a deadly weapon, rape, stalking, and child abuse.

Officials say one man walked by two other men being arrested outside a hotel but still met with the undercover officer in her room -- where he opened the blinds to watch the arrests unfold.