It's urgent to ask questions

That depends on not knowing. It doesn't matter if you don't know. If your friend also works in that hotel, he is suspected of organizing prostitution; If you just know the situation, don't explain it, and make a false certificate, it doesn't constitute a crime; If it is a lie, it can constitute a crime of harboring; If it is in the case of police arrest, providing assistance such as property and shelter can constitute a crime of harboring; Please entrust a lawyer as soon as possible! They are professionals.