In my story, one of the MCs beats a bad guy to death in an alley then goes to hide out in a pub out on the street. While in the pub, the police and paramedics and the like come to assess the situation. A police officer comes into the pub. Now here's my question. Is it accurate for the police officer to keep everyone in the pub, no one is allowed to leave, until everyone has been spoken to about what they may have witnessed? Are the police allowed to do that or would people be allowed to leave if they didn't want to testify?