Based on the context and the answer, generate a question. 

Context: We were all in the basement , probably 30 of us when there was a knock at the door . The cops ! My friends parents were so absolutely cool and bold faced lied to the police that there was noone besides them home , even though there were 15 + cars parked in front of their house . For some reason the police accepted their story and left .

Answer:

There was a loud party .



What may have caused the police to knock on the door ?