FARGO (KFGO) – Fargo-Moorhead area law enforcement agencies are investigating a series of robberies that have been targeting men who are lured by online prostitution ads.

A search warrant affidavit obtained by KFGO News says in at least two instances, the victims were duped into visiting a south Fargo apartment at 1818 2nd Ave. South, where they believed they would meet a prostitute.

The victims communicated with the suspects through text messages after seeing the fake ads on the website “skipthegames.com.”

One victim told investigators that after he arrived and paid a woman in advance, a man appeared from a bedroom and held a stun gun to the victim’s neck while the woman removed the victim’s wallet and cell phone.

Another victim told police that he was approached in the building by four men who were armed with a gun, knife and pepper spray. The man said his wallet, cash, car keys and cell phone were stolen.

Both victims told investigators that they feared for their lives.

A police surveillance camera was set up near the apartment building to monitor the suspects’ activities. Police said the camera was placed there because of an increase in “violent criminal activity over the course of several months.”

Fargo Police Dept. spokeswoman Jessica Schindeldecker says it’s a “very complex investigation” and involves “multiple incidents.” Several people have been questioned since the investigation began in June.

Schindeldecker says local and federal law enforcement agencies including the Dept. of Homeland Security are investigating.