CASPER, Wyo. — Casper police have arrested four women and one man in connection to an undercover prostitution operation.

The operation on Thursday was part of an annual nationwide effort by law enforcement to retrieve underage victims of sex trafficking.

The women were arrested on suspicion of prostitution and the man was arrested on suspicion of soliciting prostitutes.

Casper police contacted the women through online advertisements, offering to pay cash for sexual acts. Police arrested the women when they arrived at a location they had previously agreed to meet.

Police arrested the man after he responded to an online ad posted by an undercover officer posing as a sex worker. The man agreed to pay the officer with a cheeseburger in exchange for sex.