• Four girls are accused of being the man's girlfriend.
• His girlfriend is lying.
• Two girls are innocent and telling the truth.
• The other girl is the man's sister who is helping the girlfriend lie.
The statements of the four female suspects are as follows:
- Anne: "Megan is his girlfriend".
- Emily: "Anne is lying".
- Viola: "Emily is lying".
- Megan: "Viola is not his sister".