Amber Rose -- Victim in Alleged Prostitution Ring

Amber Rose was being used to lure models into prostitution ... and she had no idea.

TMZ has learned, the LAPD is now investigating a company that was soliciting models "for a paid celebrity photoshoot and clothing line."

Aspiring models who contacted the company after seeing an Instagram ad were then told Amber Rose was a key person in picking the models.

The company -- which was allegedly trying to lure the models into prostitution -- enticed them by setting up what they called a FaceTime session with Amber.

When the models called in, they saw Amber struggling with a bad connection, that eventually failed. What the models didn't know ... the company took an old video from Amber's Ustream and made it look like she was actually on the phone.

Eventually the company told the models they would be set up "on dates with rich guy," with a catch. The company would text the model, asking if they would be willing to be intimate. If so, it would help them get bigger projects, and working with Amber might help them.

One of the models went to LAPD Monday and filed a police report, claiming the company was trying to rope her into a prostitution ring. The LAPD is investigating.